Articles relating to physics advanced lab courses
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Last updated August 22, 2024
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• Physics Educational Research

  • assessment

    • Qubit quantum mechanics with correlated-photon experiments

      • Galvez, Enrique J., Am. J. Phys. 78, 510-519 (2010)
      • https://doi.org/10.1119/1.3337692
      • A matrix-based formalism is used to explain the results of undergraduate level quantum mechanics experiments with correlated photons. The article includes new variations of experiments and new results. A discussion of our experience with a correlated-photon laboratory component for an undergraduate course on quantum mechanics is presented.
    • The process of transforming an advanced lab course: Goals, curriculum, and assessments

      • Zwickl, Benjamin M.; Finkelstein, Noah; Lewandowski, H. J., Am. J. Phys. 81, 63-70 (2013)
      • https://doi.org/10.1119/1.4768890
      • A thoughtful approach to designing and improving labs, particularly at the advanced level, is critical for the effective preparation of physics majors for professional work in industry or graduate school. With that in mind, physics education researchers in partnership with the physics faculty at the University of Colorado Boulder have overhauled the senior-level Advanced Physics Lab course. The transformation followed a three part process of establishing learning goals, designing curricula that align with the goals, and assessment. Similar efforts have been carried out in physics lecture courses at the University of Colorado Boulder, but this is the first systematic research-based revision of one of our laboratory courses. The outcomes of this effort include a set of learning goals, a suite of new lab-skill activities and transformed optics labs, and a set of assessments specifically tailored for a laboratory environment. While the particular selection of advanced lab experiments varies widely between institutions, the overall transformation process, the learning goals, and the assessments are broadly applicable to the instructional lab community. (C) 2013 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4768890]
    • Epistemology and expectations survey about experimental physics: Development and initial results

      • Zwickl, Benjamin M.; Hirokawa, Takako; Finkelstein, Noah; Lewandowski, H. J., PHYSICAL REVIEW SPECIAL TOPICS-PHYSICS EDUCATION RESEARCH 10, 10120 (2014)
      • https://doi.org/10.1103/PhysRevSTPER.10.010120
      • In response to national calls to better align physics laboratory courses with the way physicists engage in research, we have developed an epistemology and expectations survey to assess how students perceive the nature of physics experiments in the contexts of laboratory courses and the professional research laboratory. The Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS) evaluates students' epistemology at the beginning and end of a semester. Students respond to paired questions about how they personally perceive doing experiments in laboratory courses and how they perceive an experimental physicist might respond regarding their research. Also, at the end of the semester, the E-CLASS assesses a third dimension of laboratory instruction, students' reflections on their course's expectations for earning a good grade. By basing survey statements on widely embraced learning goals and common critiques of teaching labs, the E-CLASS serves as an assessment tool for lab courses across the undergraduate curriculum and as a tool for physics education research. We present the development, evidence of validation, and initial formative assessment results from a sample that includes 45 classes at 20 institutions. We also discuss feedback from instructors and reflect on the challenges of large-scale online administration and distribution of results.
    • Correlating students' beliefs about experimental physics with lab course success

      • Wilcox, Bethany R.; Lewandowski, H. J., 2015 Phys. Educ. Res. Conf. , 367-370 (2015)
      • https://doi.org/10.1119/perc.2015.pr.087
      • Student learning in instructional physics labs is a growing area of research that includes studies exploring students' beliefs and expectations about experimental physics. To directly probe students' epistemologies about experimental physics and support broader lab transformation efforts both at the University of Colorado Boulder (CU) and nationally, we developed the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS). Previous work focused on establishing the accuracy and clarity of the instrument through student interviews and preliminary testing. Ongoing validation efforts include establishing the extent to which student epistemologies as measured by E-CLASS align with other measures of student learning outcomes (e.g., course grades). We find a weak but statistically significant correlation between final course grades and E-CLASS scores from two semesters of upper-division lab courses at CU and no statistically significant correlation for introductory courses. Here, we discuss implications of these findings for the validity of the E-CLASS instrument.
    • Fifteen years of quantum optics, quantum information, and nano-optics educational facility at the Institute of Optics, University of Rochester

      • Lukishova, Svetlana G., Optical Engineering 61, 81811 (2022)
      • https://doi.org/10.1117/1.OE.61.8.081811
      • The quantum optics/quantum information and nano-optics educational laboratory facility (QNOL) at the University of Rochester (UR) is located within three rooms of the Institute of Optics with a total area of 587 ft2. It has been used for teaching a 4-credit-hour QNOL class annually for 15 years. Four teaching labs were prepared on the generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach–Zehnder interferometer), (3) single-photon source I: confocal fluorescence microscopy of single nanoemitters, and (4) single-photon source II: a Hanbury Brown and Twiss setup, fluorescence antibunching. Further, based on QNOL, 1.5 to 3 h sturdy quantum “mini-labs” were developed and introduced into the required classes such that all optics students at the UR had experience with quantum labs. Monroe Community College (MCC) students participated in two mini-labs at the UR. Since 2006 to spring 2022, a total of ~850 students have utilized the labs for lab report submission (including 144 MCC students) and more than 250 students have used them for lab demonstrations. In addition, UR freshman research projects have become a very important educational activity in this facility. All developed materials and students’ reports are available at http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/. We present a description of sturdy, universally accessible experiments that can be introduced into either a separate advanced class or into classes with a large number of students. Assessment methods, evaluation of students’ knowledge, and their attitude toward their career in quantum information are discussed.
  • classroom environment / community / course design

    • Cumulative Experiments in the Advanced Laboratory

      • Graetzer, Hans G., Am. J. Phys. 40, 270-276 (1972)
      • https://doi.org/10.1119/1.1986507
      • An advanced laboratory course for physics seniors is described that uses open-ended projects organized in such a way that all of the students work on each project in turn. The students change every two or three weeks from one project to another, each time being confronted with an ongoing experiment to which they are asked to make their contribution. The laboratory notebooks contain the cumulative total of a group effort. Individual experiments can be carried to considerable depth, but at the same time the individual students are not confined to the limitations of working on just one project.
    • Simulating actual research conditions as a means of enhancing the value of advanced student laboratories

      • Buckwald, R. A., Am. J. Phys. 45, 795-796 (1977)
      • https://doi.org/10.1119/1.11050
      • A novel method of teaching advanced physics laboratories has been developed. The method simulates research conditions by creating a student‐written literature and requiring students to make researchlike decisions.
    • UMR, Incorporated: A scenario for roleplaying in an advanced undergraduate physics laboratory

      • Sparlin, Don M.; Reinisch, Louis, Am. J. Phys. 46, 45360 (1978)
      • https://doi.org/10.1119/1.11179
      • This paper describes a scenario for an upper‐level undergraduate laboratory in which the students take roles as staff members in a contract research company, UMR, Inc. Each student is assigned to a role as Senior Scientist, Researcher, or Technician based on their letter of application, resume, and personal interview. Students are assigned to research groups and participate in a project feasibility study and in writing the resulting proposal. The assembly of apparatus, data taking, and data analysis proceed as in the usual project laboratory. At the end of the semester each student writes a section of the final report and presents a 10‐min technical talk. The instructor and the assisting graduate student assume the roles of President/Chief Consultant and Vice President/Associate Consultant/Stockroom Man, respectively.
    • Contemporary electronics: A focussed concept laboratory

      • Panitz, J. A., Am. J. Phys. 70, 280-284 (2002)
      • https://doi.org/10.1119/1.1428285
      • Contemporary Electronics is an advanced undergraduate lecture and laboratory introduction to analog and digital electronics. Fundamentals of analog measurements, analog data collection, and digital data collection are included in this one-semester course. Laboratory exercises introduce diodes, transistors, operational amplifiers, and their use in simple circuits. Focus and continuity are provided by the construction of a printed circuit board nanoammeter. The nanoammeter is used to measure the tunneling current generated by a commercial field emission electron microscope. An introduction to LABVIEW programming allows each student to create a “virtual instrument” for data collection and analysis. An analysis of the tunneling data using Fowler–Nordheim theory is the focus of a midterm and a final exam.
    • Conditions for building a community of practice in an advanced physics laboratory

      • Irving, Paul W.; Sayre, Eleanor C., PHYSICAL REVIEW SPECIAL TOPICS-PHYSICS EDUCATION RESEARCH 10, 10109 (2014)
      • https://doi.org/10.1103/PhysRevSTPER.10.010109
      • We use the theory of communities of practice and the concept of accountable disciplinary knowledge to describe how a learning community develops in the context of an upper-division physics laboratory course. The change in accountable disciplinary knowledge motivates students' enculturation into a community of practice. The enculturation process is facilitated by four specific structural features of the course and supported by a primary instructional choice. The four structural features are "paucity of instructortime," " all in a room together," " long and difficult experiments," and " same experiments at different times." The instructional choice is the encouragement of the sharing and development of knowledge and understanding by the instructor. The combination of the instructional choice and structural features promotes the development of the learning community in which students engage in authentic practices of a physicist. This results in a classroom community that can provide students with the opportunity to have an accelerated trajectory towards being a more central participant of the community of a practice of physicists. We support our claims with video-based observations of laboratory classroom interactions and individual, semistructured interviews with students about their laboratory experiences and physics identity.
    • The Advanced Lab: Hallmark of an Outstanding Undergraduate Program

      • Reichert, Jonathan F., Am. J. Phys. 82, 181-182 (2014)
      • https://doi.org/10.1119/1.4863428
      • Why should students want such an advanced lab as a major part of their undergraduate program? Let me list some reasons: Some departments have come up with what they claim is a good reason for seriously limiting, or entirely eliminating a junior/senior advanced lab: “real” research. “Our students go directly into a real research laboratory, some as early as their sophomore year. They get actual research experience, not canned labs.” It sounds good: undergraduate research—the new buzz words. There is also a prestigious national award, the Apker Prize, for the best research work done by undergraduate students at two types of postsecondary schools. Even a runner-up in this competition is given high-profile national recognition. The research done by Apker recipients is undeniably impressive. But how do we know the value of other undergraduate research experiences? Were they actually appropriate and valuable for those students?
    • The role of metacognition in troubleshooting: an example from electronics

      • Van de Bogart, Kevin L.; Dounas-Frazer, Dimitri R.; Lewandowski, H. J.; Stetzer, MacKenzie R., 2015 Phys. Educ. Res. Conf. , 339-342 (2015)
      • https://doi.org/10.1119/perc.2015.pr.080
      • Students in physics laboratory courses, particularly at the upper division, are often expected to engage in troubleshooting. Although there are numerous ways in which students may proceed when diagnosing a problem, not all approaches are equivalent in terms of providing meaningful insight. It is reasonable to believe that metacognition, by assisting students in making informed decisions, is an integral component of effective troubleshooting. We report on an investigation of authentic student troubleshooting in the context of junior-level electronics courses at two institutions. Think-aloud interviews were conducted with pairs of students as they attempted to repair a malfunctioning operational-amplifier circuit. Video data from the interviews have been analyzed to examine the relationship between each group's troubleshooting activities and instances of socially mediated metacognition. We present an analysis of a short episode from one interview.
    • The impact of metacognitive activities on student attitudes towards experimental physics

      • Eblen-Zayas, Melissa, 2016 Phys. Educ. Res. Conf. , 104-107 (2016)
      • https://doi.org/10.1119/perc.2016.pr.021
      • For the past three years, I have used the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS) to monitor how an advanced lab course with a significant student driven project impacts student attitudes about experimental work. During that time period, I have increased the use of metacognitive activities that ask students to reflect on their approaches to making decisions and handling problems they encounter in the lab. Here I report on the correlation between the introduction of metacognitive activities and changes in some responses on the E-CLASS survey, as well as providing a qualitative overview of the students' metacognitive reflections.
    • Investigating student ownership of projects in an upper-division physics lab course

      • Stanley, Jacob T.; Dounas-Frazer, Dimitri R.; Kiepura, Laura; Lewandowski, H. J., 2016 Phys. Educ. Res. Conf. , 336-339 (2016)
      • https://doi.org/10.1119/perc.2016.pr.079
      • The development of students' sense of ownership of their work is recognized by many lab instructors to be an important outcome of lab courses. However, the way ownership manifests, as well as how it is developed, has not been a focus of study within the physics education research community. As a first step toward understanding what ownership looks like in this context, we are studying students' ownership of their projects in two upper-division optics courses, in which ownership is an explicit learning goal. We utilized data from the Project Ownership Survey (POS), as well as student interviews that focus on their interests, challenges, and memorable moments. The results of the POS were conflicted one portion of the survey indicated high ownership while those questions pertaining to student affect indicated otherwise. However, analysis of our interviews corroborated that students were experiencing several aspects of ownership, but the nature of their affective response was complex and dynamic.
    • Quantum optics and nano-optics teaching laboratory for the undergraduate curriculum: teaching quantum mechanics and nano-physics with photon counting instrumentation

      • Lukishova, Svetlana G., 14th Conference on Education and Training in Optics and Photonics: ETOP 2017 10452, 508-527 (2017)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10452/104522I/Quantum-optics-and-nano-optics-teaching-laboratory-for-the-undergraduate/10.1117/12.2269872.full
      • At the Institute of Optics, University of Rochester (UR), we have adapted to the main challenge (the lack of space in the curriculum) by developing a series of modular 3-hour experiments and 20-min-demonstrations based on technical elective, 4-credit-hour laboratory course “Quantum Optics and Nano-Optics Laboratory” (OPT 253/OPT453/PHY434), that were incorporated into a number of required courses ranging from freshman to senior level. Rochester Monroe Community College (MCC) students also benefited from this facility that was supported by four NSF grants. MCC students carried out two 3-hour labs on photon quantum mechanics at the UR. Since 2006, total 566 students passed through the labs with lab reports submission (including 144 MCC students) and more than 250 students through lab demonstrations. In basic class OPT 253, four teaching labs were prepared on generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach-Zehnder interferometer), (3) confocal microscope imaging of single-emitter (colloidal nanocrystal quantum dots and NV-center nanodiamonds) fluorescence within photonic (liquid crystal photonic bandgap microcavities) or plasmonic (gold bowtie nanoantennas) nanostructures, (4) Hanbury Brown and Twiss setup. Fluorescence antibunching from nanoemitters. Students also carried out measurements of nanodiamond topography using atomic force microscopy and prepared photonic bandgap materials from cholesteric liquid crystals. Manuals, student reports, presentations, lecture materials and quizzes, as well as some NSF grants’ reports are placed on a website http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/ . In 2011 UR hosted 6 professors from different US universities in three-days training of these experiments participating in the Immersion Program of the Advanced Laboratory Physics Association.
    • Recommendations for the use of notebooks in upper-division physics lab courses

      • Stanley, Jacob T.; Lewandowski, H. J., Am. J. Phys. 86, 45-53 (2018)
      • https://doi.org/10.1119/1.5001933
      • The use of lab notebooks for scientific documentation is a ubiquitous part of physics research. However, it is common for undergraduate physics laboratory courses not to emphasize the development of documentation skills, despite the fact that such courses are some of the earliest opportunities for students to start engaging in this practice. One potential impediment to the inclusion of explicit documentation training is that it may be unclear to instructors which features of authentic documentation practice are efficacious to teach and how to incorporate these features into the lab class environment. In this work, we outline some of the salient features of authentic documentation, informed by interviews with physics researchers, and provide recommendations for how these can be incorporated into the lab curriculum. We do not focus on structural details or templates for notebooks. Instead, we address holistic considerations for the purpose of scientific documentation that can guide students to develop their own documentation style. While taking into consideration all the aspects that can help improve students' documentation, it is also important to consider the design of the lab activities themselves. Students should have experience with implementing these authentic features of documentation during lab activities in order for them to find practice with documentation beneficial.
    • Using reflections to explore student learning during the project component of an advanced laboratory course

      • Cai, Bei; Mainhood, Lindsay; Knobel, Robert G., 2018 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , (2019)
      • https://www.per-central.org/items/detail.cfm?ID=14765
      • We redesigned an advanced physics laboratory course to include a project component. The intention was to address learning outcomes such as modeling, design of experiments, teamwork, and developing technical skills in using apparatus and analyzing data. The course included experimental labs in preparation for a six-week team project in which students designed and implemented a research experiment. The final assignment given to students was a reflective essay, which asked students to discuss their learning and satisfaction in doing the project. Qualitative analysis of the students' reflections showed that the majority of the students reported satisfaction and achievement, functional team dynamics, learning outcomes unique to this experience, practicing modeling skills, and potential future improvements. We suggest that reflections are useful as support for student learning as well as in guiding curricular improvements. Our findings may be useful for other course redesign initiatives incorporating project-based learning and student reflections.
    • Preliminary model for student ownership of projects

      • Dounas-Frazer, Dimitri R.; Rios, Laura; Lewandowski, H. J., 2019 Phys. Educ. Res. Conf. , 141-146 (2019)
      • https://doi.org/10.1119/perc.2019.pr.Dounas-Frazer
      • In many upper-division lab courses, instructors implement multiweek student-led projects. During such projects, students may design and carry out experiments, collect and analyze data, document and report their findings, and collaborate closely with peers and mentors. To better understand cognitive, social, and affective aspects of projects, we conducted an exploratory investigation of student ownership of projects. Ownership is a complex construct that refers to, e.g., students' willingness and ability to make strategic decisions about their project. Using data collected through surveys and interviews with students and instructors at five institutions, we developed a preliminary model for student ownership of projects. Our model describes ownership as a relationship between student and project. This relationship is characterized by student interactions with the project during three phases: choice of topic, execution of experiment, and synthesis of results. Herein, we explicate our model and demonstrate that it maps well onto students' and instructors' conceptions of ownership and ideas presented in prior literature.
    • Comparative analysis of letters and reports in an upper-division lab

      • Ramey, Charles L. I. I. I. I.; Dounas-Frazer, Dimitri R.; Thacker, Beth, 2020 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 424-429 (2020)
      • https://doi.org/10.1119/perc.2020.pr.RameyII
      • In redesigning the Modem Physics Lab at Strive University, we focused its purpose on developing writing skills. In doing that, we implemented the pedagogical method Letters Home, which offers students the ability to practice communication in the form of letters to experts and non-experts. Students were additionally tasked with writing traditional lab reports. This case study investigates 6 students' completion of 6 writing assignments (letters and reports) to a real audience. We used the AAPT guidelines to develop a qualitative coding scheme with 8 categories, and we used a linguistic analysis software program called LIWC to evaluate the assignments' authenticity, clout, tone, and analytical thinking. Our results indicate 6 of the 8 coding categories appear in at least 50% of the data. Also, letters to experts and non-experts indicated similarities in analytical thinking. Authenticity scores were higher for letters to non-experts than experts. Overall, letters and reports are similar in terms of both the AAPT-inspired codes and linguistic dimensions probed by LIWC. The similarities between the letters and lab reports from our study may be due to our curriculum redesign.
    • Remote advanced lab course: A case study analysis of open-ended projects

      • Hoehn, Jessica R.; Fox, Michael F. J.; Werth, Alexandra; Borish, Victoria; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 17, 20111 (2021)
      • https://doi.org/10.1103/PhysRevPhysEducRes.17.020111
      • The rapid transition to remote teaching in the spring of 2020 posed particular challenges for laboratory courses, which often involve students working hands-on with equipment in collaborative environments. Replicating in-person experiments was especially challenging for advanced lab courses that utilize specialized apparatus, which could not be accessed by students at home. However, physics lab instructors employed a variety of creative strategies to overcome these barriers and provide students access to lab-like learning in a remote setting. We report on one advanced lab course that used the transition to remote teaching to completely redefine the course goals and transition from traditional prescriptive labs to more open-ended projects. We conduct a case study analysis, triangulating among several data sources—survey responses and interviews from both instructor and students—to construct an in-depth understanding of the remote course and how students experienced it. Although we cannot necessarily generalize the results of this analysis to the entire student experience in the course due to the student response rate, the feedback that the course did receive from both students and the instructor was overwhelmingly positive, and the instructors are planning to retain the open-ended projects when the course returns to an in-person format. We find that the new open-ended projects afforded students opportunities to make decisions and think deeply about their experiments, which students report as contributing to their enjoyment and satisfaction with the course. Students had mixed group work experiences, with some describing positive and meaningful interactions and others describing group work as a source of frustration and stress. Additionally, some students missed being able to work hands-on with equipment, and some reported a high workload that made the course stressful. We discuss these student experiences and provide implications for both in-person and remote lab courses.
    • Sustainable education in the age of the second quantum revolution: fifteen years of the University of Rochester National Science Foundation supported efforts

      • Lukishova, Svetlana G.; Bigelow, Nicholas, Seventeenth Conference on Education and Training in Optics and Photonics: ETOP 2023 (2023), paper 127230B , 127230B (2023)
      • https://doi.org/10.1117/12.2666502
      • Quantum optics/quantum information and nano-optics educational laboratory facility (QNOL) at the University of Rochester (UR) is located within three rooms of the Institute of Optics with a total area of 587 ft2. Four teaching labs were prepared on the generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach-Zehnder interferometer), (3) single-photon source I: confocal fluorescence microscopy of single nanoemitters, and (4) single-photon source II: a Hanbury Brown and Twiss setup, fluorescence antibunching. We also describe a coherent undergraduate educational program in nanoscience/nanoengineering at the UR based on the QNOL and Integrated Nanosystems Center resources. From 2006 to May 2023, a total of ~900 students have utilized the quantum/nano labs for lab report submission (including 144 Monroe Community College students) and more than 300 students have used them for lab demonstrations. These two projects have three main outcomes: (1) developing a curriculum and offering the Certificate in Nanoscience and Nanoengineering; (2) creating an exemplary model of collaboration in quantum/nanotechnology between a university with state-of-the-art, expensive experimental facilities and a nearby two-year community college; and (3) developing universally accessible “hands-on” experiments (minilabs) on quantum/nanophotonics, learning materials, and pedagogical methods. The inexpensive mini-labs described herein can be adopted in small colleges. All developed materials and students’ reports are available at http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/. Two papers in a special issue of Optical Engineering describe these two programs with more details: https://doi.org/10.1117/1.OE.61.8.081811 and https://doi.org/10.1117/1.OE.61.8.081810.
    • Fiber optic Michelson interference experimental course towards the cultivation of undergraduates majoring in optical engineering

      • Zhang, Min; Gao, Jiaxing; Liu, Zhihai; Zhang, Yu; Zhang, Yaxun; Yang, Xinghua; Zhang, Jianzhong; Yang, Jun; Yuan, Libo, Eur. J. Phys. 44, 45702 (2023)
      • https://dx.doi.org/10.1088/1361-6404/acd286
      • With the development of optical engineering technologies, traditional experimental courses that merely demonstrate theoretical phenomena can no longer meet the demands of optical engineers’ education. In this paper, we propose an experimental course ‘Fiber-Michelson white light interference experiment’ towards the cultivation of optical engineering undergraduates and present a fiber optic system supporting the course. The proposed course integrates fiber optics and optical engineering applications with traditional Michelson interference experimental course, and the experimental system used in the course is low in cost, easy to operate, and convenient to assemble. During the class, students work as groups and have to finish three experimental tasks including the measurements of length, curvature, and refractive index. The first-hand experiences in experiments can impress students with the Michelson optic interference theory and is conductive to developing their abilities to apply optics to engineering. Students’ feedbacks are collected by questionnaire, and students recognize the necessity and effectiveness of the course.
  • learning goals

    • The process of transforming an advanced lab course: Goals, curriculum, and assessments

      • Zwickl, Benjamin M.; Finkelstein, Noah; Lewandowski, H. J., Am. J. Phys. 81, 63-70 (2013)
      • https://doi.org/10.1119/1.4768890
      • A thoughtful approach to designing and improving labs, particularly at the advanced level, is critical for the effective preparation of physics majors for professional work in industry or graduate school. With that in mind, physics education researchers in partnership with the physics faculty at the University of Colorado Boulder have overhauled the senior-level Advanced Physics Lab course. The transformation followed a three part process of establishing learning goals, designing curricula that align with the goals, and assessment. Similar efforts have been carried out in physics lecture courses at the University of Colorado Boulder, but this is the first systematic research-based revision of one of our laboratory courses. The outcomes of this effort include a set of learning goals, a suite of new lab-skill activities and transformed optics labs, and a set of assessments specifically tailored for a laboratory environment. While the particular selection of advanced lab experiments varies widely between institutions, the overall transformation process, the learning goals, and the assessments are broadly applicable to the instructional lab community. (C) 2013 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4768890]
    • Studying Expert Practices to Create Learning Goals for Electronics Labs

      • Lewandowski, H. J.; Finkelstein, Noah; Pollard, Benjamin, 2014 Phys. Educ. Res. Conf. , 155-158 (2014)
      • https://doi.org/10.1119/perc.2014.pr.035
      • Laboratory courses for upper-division undergraduates often involve sophisticated equipment, relatively small class sizes, and extended hands-on projects. These courses present distinct challenges and opportunities for the physics education research community as these features are not often present in other undergraduate courses. Here, we focus on an upper-division lab-based electronics course. As a first step in establishing learning goals for upper-division electronics, we interviewed graduate students and faculty at the University of Colorado Boulder about the use of electronics in their own research labs. The content-specific nature of electronics courses parallels the hands-on experience of graduate student researchers, so focusing on the experiences of graduate students is ideal for informing lab course reform. From their interview responses, we developed a framework for classifying applications of electronics. We identify five types of use and four forms of interaction with electronics content that are consistently identified by faculty and graduate students. However, we see variations between faculty and graduate students regarding how electronics is learned.
    • Seeing quantum mechanics: The role of quantum experiments

      • Borish, Victoria; Werth, Alexandra; Lewandowski, H. J., 2022 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 57-63 (2022)
      • https://doi.org/10.1119/perc.2022.pr.Borish
      • The second quantum revolution has prompted not only research in quantum science and technology, but also research on how best to educate students who may enter this burgeoning field. Much of the conversation around quantum science education has focused on students' conceptual learning or skills desired by potential employers; there has been an absence of work understanding how laboratory courses and experiments contribute to undergraduate quantum education. To begin understanding the role quantum experiments may play, we surveyed instructors who implement experiments with single and entangled photons in undergraduate lab courses and found that one of the most important learning goals was to "see quantum mechanics in real life." To better understand this goal, we interviewed 15 of the surveyed instructors asking what seeing quantum mechanics means to them and why they believe it is an important part of students' education. We present emergent themes from a qualitative coding analysis of these interviews, which begin to elucidate how instructors think about seeing quantum mechanics and what learning goals instructors hope seeing quantum mechanics-and working with quantum experiments more generally-will help students achieve.
    • Fifteen years of quantum optics, quantum information, and nano-optics educational facility at the Institute of Optics, University of Rochester

      • Lukishova, Svetlana G., Optical Engineering 61, 81811 (2022)
      • https://doi.org/10.1117/1.OE.61.8.081811
      • The quantum optics/quantum information and nano-optics educational laboratory facility (QNOL) at the University of Rochester (UR) is located within three rooms of the Institute of Optics with a total area of 587 ft2. It has been used for teaching a 4-credit-hour QNOL class annually for 15 years. Four teaching labs were prepared on the generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach–Zehnder interferometer), (3) single-photon source I: confocal fluorescence microscopy of single nanoemitters, and (4) single-photon source II: a Hanbury Brown and Twiss setup, fluorescence antibunching. Further, based on QNOL, 1.5 to 3 h sturdy quantum “mini-labs” were developed and introduced into the required classes such that all optics students at the UR had experience with quantum labs. Monroe Community College (MCC) students participated in two mini-labs at the UR. Since 2006 to spring 2022, a total of ~850 students have utilized the labs for lab report submission (including 144 MCC students) and more than 250 students have used them for lab demonstrations. In addition, UR freshman research projects have become a very important educational activity in this facility. All developed materials and students’ reports are available at http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/. We present a description of sturdy, universally accessible experiments that can be introduced into either a separate advanced class or into classes with a large number of students. Assessment methods, evaluation of students’ knowledge, and their attitude toward their career in quantum information are discussed.
    • Implementation and goals of quantum optics experiments in undergraduate instructional labs

      • Borish, Victoria; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 19, 10117 (2023)
      • https://link.aps.org/doi/10.1103/PhysRevPhysEducRes.19.010117
      • As quantum information science and technology (QIST) is becoming more prevalent and occurring not only in research labs but also in industry, many educators are considering how best to incorporate learning about quantum mechanics into various levels of education. Although much of the focus has been on quantum concepts in nonlab courses, current work in QIST has a substantial experimental component. Many instructors of undergraduate lab courses want to provide their students the opportunity to work with quantum experiments. One common way this is done is through a sequence of quantum optics experiments often referred to as the “single-photon experiments.” These experiments demonstrate fundamental quantum phenomena with equipment common to research labs; however, they are resource intensive and cannot be afforded by all institutions. It is therefore imperative to know what unique affordances these experiments provide to students. As a starting point, we surveyed and interviewed instructors who use the single-photon experiments in undergraduate courses, asking how and why they use the experiments. We describe the most commonly used experiments in both quantum and beyond-first-year lab courses, the prevalence of actions the students perform, and the learning goals, ranging from conceptual knowledge to lab skills to student affect. Finally, we present some strategies from these data demonstrating how instructors have addressed the common challenges of preparing students to work with conceptually and technically complex experiments and balancing the practice of technical skills with the completion of the experiments.
    • Seeing quantum effects in experiments

      • Borish, Victoria; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 19, 20144 (2023)
      • https://doi.org/10.1103/PhysRevPhysEducRes.19.020144
      • [This paper is part of the Focused Collection on Instructional labs: Improving traditions and new directions.] Quantum mechanics is a field often considered very mathematical, abstract, and unintuitive. One way some instructors are hoping to help familiarize their students with these complex topics is to have the students see quantum effects in experiments in undergraduate instructional labs. Here, we present results from an interview study about what it means to both instructors and students to see quantum effects in experiments. We focus on a popular set of quantum optics experiments and find that students believe they are observing quantum effects and achieving related learning goals by working with these experiments. Although it is not possible to see the quantum phenomena directly with their eyes, students point out different aspects of the experiments that contribute to them observing quantum effects. This often includes seeing the experimental results, sometimes in conjunction with interacting with or understanding part of the experiment. There is additional variation across student achievement of the various related learning goals, ranging from many of the students being excited about these experiments and making a connection between the mathematical theory and the experiments to only some of the students seeing a connection between these experiments and quantum technologies. This work can help instructors consider the importance and framing of quantum experiments and raises questions about when and how in the curriculum quantum experiments can be best utilized and how to make related learning goals available to all students., This article appears in the following collection:
  • modeling

    • Incorporating learning goals about modeling into an upper-division physics laboratory experiment

      • Zwickl, Benjamin M.; Finkelstein, Noah; Lewandowski, H. J., Am. J. Phys. 82, 876-882 (2014)
      • https://doi.org/10.1119/1.4875924
      • Implementing a laboratory activity involves a complex interplay among learning goals, available resources, feedback about the existing course, best practices for teaching, and an overall philosophy about teaching labs. Building on our previous work, which described a process of transforming an entire lab course, we now turn our attention to how an individual lab activity on the polarization of light was redesigned to include a renewed emphasis on one broad learning goal: modeling. By using this common optics lab as a concrete case study of a broadly applicable approach, we highlight many aspects of the activity development and show how modeling is used to integrate sophisticated conceptual and quantitative reasoning into the experimental process through the various aspects of modeling: constructing models, making predictions, interpreting data, comparing measurements with predictions, and refining models. One significant outcome is a natural way to integrate an analysis and discussion of systematic error into a lab activity.
    • Making Models of Measurement Tools: Examples from Think-Aloud Student Interviews

      • Zwickl, Benjamin M.; Hu, Dehui; Finkelstein, Noah; Lewandowski, H. J., 2014 Phys. Educ. Res. Conf. , 291-294 (2014)
      • https://doi.org/10.1119/perc.2014.pr.069
      • Constructing and using models are core scientific practices that have gained significant attention within K-12 and higher education. Although modeling is a broadly applicable process, within physics education, it has been preferentially applied to the iterative development of broadly-applicable principles (e.g., Newton's laws of motion in introductory mechanics). We show how similar modeling processes can be invoked as a means to understand the real-world complexities of experimental apparatus, including the measurement tools, in upper-division laboratory courses. In the context of a think-aloud experimental activity involving optics and electronics, we document examples where students apply all of the key facets of modeling to their apparatus and measurement tools: construction, prediction, interpretation of data, identification of model limitations, and revision. A modeling perspective reframes many of the seemingly arbitrary technical details of measurement tools and apparatus as an opportunity for authentic and engaging scientific sense-making.
    • Redesigning a junior-level electronics course to support engagement in scientific practices

      • Lewandowski, H. J.; Finkelstein, Noah, 2015 Phys. Educ. Res. Conf. , 191-194 (2015)
      • https://doi.org/10.1119/perc.2015.pr.043
      • Building on successful work on studying and transforming our senior-level Advanced Lab course, we have transformed our junior-level Electronics course to engage students in a variety of authentic scientific practices, including constructing, testing, and refining models of canonical measurement tools and analog circuits. We describe our approach to the transformation, provide a framework for incorporating authentic scientific practices, and present initial outcomes from the project. As part of the broader assessment of these course transformations, we examine one course learning outcome: development of the ability to model measurement systems. We demonstrate that in the transformed course students demonstrate greater likelihood of identifying discrepancies between the measurement and the model and significantly greater tendencies to refine their models to reconcile with the measurement.
    • Model-based reasoning in the physics laboratory: Framework and initial results

      • Zwickl, Benjamin M.; Hu, Dehui; Finkelstein, Noah; Lewandowski, H. J., PHYSICAL REVIEW SPECIAL TOPICS-PHYSICS EDUCATION RESEARCH 11, 20113 (2015)
      • https://doi.org/10.1103/PhysRevSTPER.11.020113
      • [This paper is part of the Focused Collection on Upper Division Physics Courses.] We review and extend existing frameworks on modeling to develop a new framework that describes model-based reasoning in introductory and upper-division physics laboratories. Constructing and using models are core scientific practices that have gained significant attention within K-12 and higher education. Although modeling is a broadly applicable process, within physics education, it has been preferentially applied to the iterative development of broadly applicable principles (e.g., Newton's laws of motion in introductory mechanics). A significant feature of the new framework is that measurement tools (in addition to the physical system being studied) are subjected to the process of modeling. Think-aloud interviews were used to refine the framework and demonstrate its utility by documenting examples of model-based reasoning in the laboratory. When applied to the think-aloud interviews, the framework captures and differentiates students' model-based reasoning and helps identify areas of future research. The interviews showed how students productively applied similar facets of modeling to the physical system and measurement tools: construction, prediction, interpretation of data, identification of model limitations, and revision. Finally, we document students' challenges in explicitly articulating assumptions when constructing models of experimental systems and further challenges in model construction due to students' insufficient prior conceptual understanding. A modeling perspective reframes many of the seemingly arbitrary technical details of measurement tools and apparatus as an opportunity for authentic and engaging scientific sense making.
    • Instructor perspectives on iteration during upper-division optics lab activities

      • Dounas-Frazer, Dimitri R.; Stanley, Jacob T.; Lewandowski, H. J., 2017 Phys. Educ. Res. Conf. , 116-119 (2017)
      • https://doi.org/10.1119/perc.2017.pr.024
      • Although developing proficiency with modeling is a nationally endorsed learning outcome for upper-division undergraduate physics lab courses, no corresponding research-based assessments exist. Our longterm goal is to develop assessments of students' modeling ability that are relevant across multiple upper-division lab contexts. To this end, we interviewed 19 instructors from 16 institutions about optics lab activities that incorporate photodiodes. Interviews focused on how those activities were designed to engage students in some aspects of modeling. We find that, according to many interviewees, iteration is an important aspect of modeling. In addition, interviewees described four distinct types of iteration: revising apparatuses, revising models, revising data-taking procedures, and repeating data collection using existing apparatuses and procedures. We provide examples of each type of iteration, and discuss implications for the development of future modeling assessments.
    • The Modelling Framework for Experimental Physics: description, development, and applications

      • Dounas-Frazer, Dimitri R.; Lewandowski, H. J., Eur. J. Phys. 39, 64005 (2018)
      • https://doi.org/10.1088/1361-6404/aae3ce
      • The ability to construct, use, and revise models is a crucial experimental physics skill. Many existing frameworks describe modelling in science education at introductory levels. However, most have limited applicability to the context of upper-division physics lab courses or experimental physics. Here, we review the Modelling Framework for Experimental Physics, a theoretical framework tailored to labs and experimentation. A key feature of the framework is recursive interaction between models and apparatus. Models are revised to account for new evidence produced by apparatus, and apparatus are revised to better align with the simplifying assumptions of models. Another key feature is the distinction between the physical phenomenon being investigated and the measurement equipment used to conduct the investigation. Models of physical systems facilitate explanation or prediction of phenomena, whereas models of measurement systems facilitate interpretation of data. We describe the framework, provide a chronological history of its development, and summarise its applications to research and curricular design. Ultimately, we argue that the Modelling Framework is a theoretically sound and well-tested tool that is applicable to multiple physics domains and research purposes. In particular, it is useful for characterising students’ approaches to experimentation, designing or evaluating curricula for lab courses, and developing instruments to assess students’ experimental modelling skills.
    • Creating a coupled multiple response assessment for modeling in lab courses

      • Pollard, Benjamin; Fox, Michael F. J.; Rios, Laura; Lewandowski, H. J., 2020 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 400-405 (2020)
      • https://www.webofscience.com/api/gateway?GWVersion=2&SrcAuth=DynamicDOIConfProc&SrcApp=WOS&KeyAID=10.1119%2Fperc.2020.pr.Pollard&DestApp=DOI&SrcAppSID=USW2EC0D4DjiU3wsyrv0ez0IKreaU&SrcJTitle=2020+PHYSICS+EDUCATION+RESEARCH+CONFERENCE+%28PERC%29&DestDOIRegistrantName=American+Association+of+Physics+Teachers
      • Research-based assessment instruments (RBAIs) are essential tools to measure aspects of student learning and improve pedagogical practice. RBAIs are designed to measure constructs related to a well-defined learning goal. However, relatively few RBAIs exist that are suitable for the specific learning goals of upper-division physics lab courses. One such learning goal is modeling, the process of constructing, testing, and refining models of physical and measurement systems. Here, we describe the creation of one component of an RBAI to measure proficiency with modeling. The RBAI is called the Modeling Assessment for Physics Laboratory Experiments (MAPLE). For use with large numbers of students, MAPLE must be scalable, which includes not requiring impractical amounts of labor to analyze its data as is often the case with large free-response assessments. We, therefore, use the coupled multiple response (CMR) format, from which data can be analyzed by a computer, to create items for measuring student reasoning in this component of MAPLE. We describe the process we used to create a set of CMR items for MAPLE, provide an example of this process for an item, and lay out an argument for construct validity of the resulting items based on our process.
    • Student engagement with modeling in multiweek student-designed lab projects

      • Borish, Victoria; Hoehn, Jessica R.; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 18, 20135 (2022)
      • https://doi.org/10.1103/PhysRevPhysEducRes.18.020135
      • Modeling, which is the process of constructing, testing, and refining models, is an important skill in experimental physics, and thus a learning goal of many physics laboratory classes. One promising approach to help students develop modeling skills is to incorporate multiweek student-designed projects into lab courses. In order to assess the potential benefits of these projects in enhancing students’ modeling abilities, we analyzed projects from three upper-division lab courses at different institutions. By looking at written student coursework and student interviews, we investigated which parts of the modeling process the students from each project undertook, and how this engagement in modeling differed depending on features of the projects. The projects in our dataset varied widely, showing evidence of different ways students engaged with model construction and revisions. We observed that the features of the projects, such as the goal of the project and the complexity of the required apparatus, were associated with the ways in which the students constructed models and enacted revisions. This has implications for how instructors may choose to frame and structure courses with student-designed lab projects.
  • uncertainty

    • Student reasoning about sources of experimental measurement uncertainty in quantum versus classical mechanics

      • Stump, Emily M.; White, Courtney L.; Passante, Gina; Holmes, N. G., 2020 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 527-532 (2020)
      • https://doi.org/10.1119/perc.2020.pr.Stump
      • Measurement uncertainty and experimental error are important concepts taught in undergraduate physics laboratories. Although student ideas about error and uncertainty in introductory classical mechanics lab experiments have been studied extensively, there is relatively limited research on student thinking about experimental measurement uncertainty in quantum mechanics. In this work, we used semi-structured interviews to study advanced physics students' interpretations of fictitious data distributions from two common undergraduate laboratory experiments in quantum mechanics and one in classical mechanics. To analyze these interpretations, we developed a coding scheme that classifies student responses based on what factors they believe create uncertainty and differentiates between different types of uncertainty (e.g. imprecision, inaccuracy). We found that participants in our study expressed a variety of ideas about measurement uncertainty that varied with the context (classical/quantum) and the type of uncertainty.
    • Undergraduate students’ reasoning about the quality of experimental measurements of covarying secondary data

      • Kampen, Paul van; Gkioka, Olga, Eur. J. Phys. 42, 45704 (2021)
      • https://dx.doi.org/10.1088/1361-6404/abfd27
      • We have investigated how first-year and second-year university students judge the quality of secondary experimental data consisting of measurements of covarying quantities, and to what extent they consider multiple measurements of covarying quantities as a single data set characterised by its mean and spread. Five cohorts of students at two universities participated in the study. They offered written responses to three open-ended questions. Individual follow-up interviews were conducted with fourteen students that were based on their previous written answers to understand their reasoning in more depth. A fine-grained analysis was undertaken to unpack students’ reasoning by grouping the criteria they used to judge the quality of the data into three broad categories: criteria independent of the data, criteria that based on the variation of the raw data, and criteria based on the variation of the derived quantity. We argue that responses in each category can be linked to different learning objectives. The students proposed various actions to increase the trustworthiness of the covarying data or a conclusion based on it. We have investigated to what extent decisions and proposed actions were consistent. Students generally showed a fragmented and primarily qualitative understanding of the concepts of mean, uncertainty, and line of best fit. Many students proposed to determine the value of a derived quantity by applying the equation relating it to the measurands to individual data points, all data points, or all data points except for outliers. Students appear to consider the best fit line as a tool for eliminating outliers, but much less frequently as a way to determine a derived quantity. We discuss implications for instructional practice and further research.
    • Survey of physics reasoning on uncertainty concepts in experiments: An assessment of measurement uncertainty for introductory physics labs

      • Vignal, Michael; Geschwind, Gayle; Pollard, Benjamin; Henderson, Rachel; Caballero, Marcos D.; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 19, 20139 (2023)
      • https://doi.org/10.1103/PhysRevPhysEducRes.19.020139
      • [This paper is part of the Focused Collection on Instructional labs: Improving traditions and new directions.] Measurement uncertainty is a critical feature of experimental research in the physical sciences, and the concepts and practices surrounding measurement uncertainty are important components of physics lab courses. However, there has not been a broadly applicable, research-based assessment tool that allows physics instructors to easily measure students’ knowledge of measurement uncertainty concepts and practices. To address this need, we employed evidence-centered design to create the Survey of Physics Reasoning on Uncertainty Concepts in Experiments (SPRUCE). SPRUCE is a pre-post assessment instrument intended for use in introductory (first and second year) physics lab courses to help instructors and researchers identify student strengths and challenges with measurement uncertainty. In this paper, we discuss the development of SPRUCE’s assessment items guided by evidence-centered design, focusing on how instructors’ and researchers’ assessment priorities were incorporated into the assessment items and how students’ reasoning from pilot testing informed decisions around item answer options. We also present an example of some of the feedback an instructor would receive after implementing SPRUCE in a pre-post fashion, along with a brief discussion of how that feedback could be interpreted and acted upon., This article appears in the following collection:
  • writing

    • Recommendations for the use of notebooks in upper-division physics lab courses

      • Stanley, Jacob T.; Lewandowski, H. J., Am. J. Phys. 86, 45-53 (2018)
      • https://doi.org/10.1119/1.5001933
      • The use of lab notebooks for scientific documentation is a ubiquitous part of physics research. However, it is common for undergraduate physics laboratory courses not to emphasize the development of documentation skills, despite the fact that such courses are some of the earliest opportunities for students to start engaging in this practice. One potential impediment to the inclusion of explicit documentation training is that it may be unclear to instructors which features of authentic documentation practice are efficacious to teach and how to incorporate these features into the lab class environment. In this work, we outline some of the salient features of authentic documentation, informed by interviews with physics researchers, and provide recommendations for how these can be incorporated into the lab curriculum. We do not focus on structural details or templates for notebooks. Instead, we address holistic considerations for the purpose of scientific documentation that can guide students to develop their own documentation style. While taking into consideration all the aspects that can help improve students' documentation, it is also important to consider the design of the lab activities themselves. Students should have experience with implementing these authentic features of documentation during lab activities in order for them to find practice with documentation beneficial.
    • Using reflections to explore student learning during the project component of an advanced laboratory course

      • Cai, Bei; Mainhood, Lindsay; Knobel, Robert G., 2018 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , (2019)
      • https://www.per-central.org/items/detail.cfm?ID=14765
      • We redesigned an advanced physics laboratory course to include a project component. The intention was to address learning outcomes such as modeling, design of experiments, teamwork, and developing technical skills in using apparatus and analyzing data. The course included experimental labs in preparation for a six-week team project in which students designed and implemented a research experiment. The final assignment given to students was a reflective essay, which asked students to discuss their learning and satisfaction in doing the project. Qualitative analysis of the students' reflections showed that the majority of the students reported satisfaction and achievement, functional team dynamics, learning outcomes unique to this experience, practicing modeling skills, and potential future improvements. We suggest that reflections are useful as support for student learning as well as in guiding curricular improvements. Our findings may be useful for other course redesign initiatives incorporating project-based learning and student reflections.
    • Investigating students' views about the role of writing in physics lab classes

      • Hoehn, Jessica R.; Lewandowski, H. J., 2020 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 216-221 (2020)
      • https://doi.org/10.1119/perc.2020.pr.Hoehn
      • Writing is an important aspect of experimental physics. Physics laboratory classes typically engage students in scientific documentation and writing in the forms of lab notebooks, reports, or proposals. Instructors of these classes may have a variety of motivations for incorporating writing. We previously developed a framework for thinking about the role of writing in physics lab classes that lists and categorizes possible goals instructors may have for writing. Here, we use that framework as a research tool to investigate students' views about, and experiences with, writing in lab classes, and experimental physics more generally. We present results of an analysis of student responses to weekly reflection questions throughout one semester of an advanced lab class. The results suggest that students think about writing in a variety of ways, and that the context and framing of the course may impact student thinking about the purpose of writing.
    • Framework of goals for writing in physics lab classes

      • Hoehn, Jessica R.; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 16, 10125 (2020)
      • https://doi.org/10.1103/PhysRevPhysEducRes.16.010125
      • Writing is an integral part of the process of science. In the undergraduate physics curriculum, the most common place that students engage with scientific writing is in lab classes, typically through lab notebooks, reports, and proposals. There has not been much research on why and how we include writing in physics lab classes, and instructors may incorporate writing for a variety of reasons. Through a broader study of multiweek projects in advanced lab classes, we have developed a framework for thinking about and understanding the role of writing in lab classes. This framework defines and describes the breadth of goals for incorporating writing in lab classes, and is a tool we can use to begin to understand why, and subsequently how, we teach scientific writing in physics.
    • Comparative analysis of letters and reports in an upper-division lab

      • Ramey, Charles L. I. I. I. I.; Dounas-Frazer, Dimitri R.; Thacker, Beth, 2020 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 424-429 (2020)
      • https://doi.org/10.1119/perc.2020.pr.RameyII
      • In redesigning the Modem Physics Lab at Strive University, we focused its purpose on developing writing skills. In doing that, we implemented the pedagogical method Letters Home, which offers students the ability to practice communication in the form of letters to experts and non-experts. Students were additionally tasked with writing traditional lab reports. This case study investigates 6 students' completion of 6 writing assignments (letters and reports) to a real audience. We used the AAPT guidelines to develop a qualitative coding scheme with 8 categories, and we used a linguistic analysis software program called LIWC to evaluate the assignments' authenticity, clout, tone, and analytical thinking. Our results indicate 6 of the 8 coding categories appear in at least 50% of the data. Also, letters to experts and non-experts indicated similarities in analytical thinking. Authenticity scores were higher for letters to non-experts than experts. Overall, letters and reports are similar in terms of both the AAPT-inspired codes and linguistic dimensions probed by LIWC. The similarities between the letters and lab reports from our study may be due to our curriculum redesign.
• Experiments

  • acoustics

    • Acoustic quality factor and energy losses in cylindrical pipes

      • Moloney, Michael J.; Hatten, Daniel L., Am. J. Phys. 69, 311-314 (2001)
      • https://doi.org/10.1119/1.1308264
      • The quality factor Q of a damped oscillator equals 2π times the ratio of stored energy to the energy dissipated per cycle. This makes Q a sensitive probe of energy losses. Using modest equipment, we measured the acoustical Q for a set of cylindrical pipes having the same resonant frequency, but different diameters D. The graph of Q vs D could be well fitted with two parameters, one of which corresponds to energy loss via radiation from the ends of the pipe, and the other to thermal and viscous losses very close to the pipe wall. The wall loss parameter was quite constant no matter where the pipes were located, but the radiative loss parameter varied significantly with location inside a room, suggesting that room reflections affected the sound radiated from the pipe. This study offers valuable insights at no great expense, and could be the basis of an upper-division undergraduate laboratory experiment.
    • Laboratory exercises on oscillation modes of pipes

      • Haeberli, Willy, Am. J. Phys. 77, 204-208 (2009)
      • https://doi.org/10.1119/1.3050179
      • This paper describes an improved lab setup to study the vibrations of air columns in pipes. Features of the setup include transparent pipes which reveal the position of a movable microphone inside the pipe; excitation of pipe modes with a miniature microphone placed to allow access to the microphone stem for open, closed, or conical pipes; and sound insulation to avoid interference between different setups in a student lab. The suggested experiments on the modes of open, closed, and conical pipes, the transient response of a pipe, and the effect of pipe diameter are suitable for introductory physics laboratories, including laboratories for nonscience majors and music students, and for more advanced undergraduate laboratories. For honors students or for advanced laboratory exercises, the quantitative relation between the resonance width and damping time constant is of interest.
    • Intonation and compensation of fretted string instruments

      • Varieschi, Gabriele U.; Gower, Christina M., Am. J. Phys. 78, 47-55 (2010)
      • https://doi.org/10.1119/1.3226563
      • We discuss theoretical and physical models that are useful for analyzing the intonation of musical instruments such as guitars and mandolins and can be used to improve the tuning on these instruments. The placement of frets on the fingerboard is designed according to mathematical rules and the assumption of an ideal string. The analysis becomes more complicated when we include the effects of deformation of the string and inharmonicity due to other string characteristics. As a consequence, perfect intonation of all the notes on the instrument cannot be achieved, but complex compensation procedures can be introduced to minimize the problem. To test the validity of these procedures, we performed extensive measurements using standard monochord sonometers and other acoustical devices, confirming the correctness of our theoretical models. These experimental activities can be integrated into acoustics courses and laboratories and can become a more advanced version of basic experiments with monochords and sonometers.
    • Acoustic resonance spectroscopy for the advanced undergraduate laboratory

      • Franco-Villafañe, J. A.; Flores-Olmedo, E.; Báez, G.; Gandarilla-Carrillo, O.; Méndez-Sánchez, R. A., Eur. J. Phys. 33, 1761 (2012)
      • https://iopscience.iop.org/article/10.1088/0143-0807/33/6/1761/meta
      • nan
    • Optics laboratory extensions

      • Vogel, Ron, Eur. J. Phys. 36, 55045 (2015)
      • https://dx.doi.org/10.1088/0143-0807/36/5/055045
      • Most of the optics experiments done in beginning or advanced labs have ultrasonic analogs which can be used to demonstrate much of what can be done in the optics labs. These analogs can be used as a substitute for the corresponding optics experiments or in conjunction with them. And the ultrasonic experiments can be used to demonstrate several phenomena of wave propagation that are difficult to do with optics. For example, experiments can be done to observe the effects in the time domain of pulse excitation, something which is rarely done in optics, and the results used to expand student understanding of optics. The methods of several of these experiments are the subject of this paper, and comparisons will be made with what can be demonstrated with the corresponding optics experiments.
    • Measurement of the sound absorption coefficient for an advanced undergraduate physics laboratory

      • Macho-Stadler, E.; Elejalde-García, M. J., Eur. J. Phys. 38, 55703 (2017)
      • https://dx.doi.org/10.1088/1361-6404/aa78b1
      • We present a simple experiment that allows advanced undergraduates to learn the basics of the acoustic properties of materials. The impedance tube-standing wave method is applied to study the normal absorption coefficient of acoustics insulators. The setup includes a tube, a speaker, a microphone, a digital function generator and an oscilloscope, material available in an undergraduate laboratory. Results of the change of the absorption coefficient with the frequency, the sample thickness and the sample density are analysed and compared with those obtained with a commercial system.
    • Inharmonicity in plucked guitar strings

      • Murray, Chris J.; Whitfield, Scott B., Am. J. Phys. 90, 487-493 (2022)
      • https://doi.org/10.1119/5.0064373
      • We have considered the vibration of various types of pinned guitar strings and have investigated the deviation of the partials from integer multiples of the string's fundamental vibration frequency. We measured the inharmonicity parameter B and compared it to a direct calculation based on a model equation. We generally found very good agreement between the two determinations of B for monofilament strings, but perhaps not surprisingly, we find rather poor agreement for wound strings. Furthermore, we show that the methodology used to carry out this experiment can easily serve as the basis for an upper division physics laboratory on physical acoustics including a more thorough investigation of the classical wave equation in a real-world application.
    • A graduate laboratory experiment to study the dynamics of an acoustically levitated particle

      • Dolev, Amit; Noseda, Lorenzo; Yalcin, Bora; Sakar, Mahmut Selman, Eur. J. Phys. 44, 65801 (2023)
      • https://dx.doi.org/10.1088/1361-6404/acf0a4
      • The comprehension of physical wave phenomena is imperative for students in the fields of engineering and basic sciences. Laboratory experiments that involve generation of acoustic waves can be used to explain advanced nonlinear wave phenomena. Acoustic levitation is a method for stably suspending and trapping objects in mid-air using acoustic radiation forces. This paper discusses an experimental apparatus that offers an economical means to demonstrate the acoustic levitation of polystyrene particles while enabling the investigation of stability and nonlinear dynamics of the trapped particles. Additionally, this platform offers the potential to examine other phenomena, such as the interaction forces between multiple acoustically levitated particles. The mechanical design of the system along with the data acquisition and control techniques are thoroughly explained.
  • astrophysics

    • High‐resolution solar spectroscopy in the undergraduate physics laboratory

      • Ratcliff, Stephen J.; Noss, Darcy K.; Dunham, Jeffrey S.; Anthony, Eric B.; Cooley, John H.; Alvarez, Alberto, Am. J. Phys. 60, 645-649 (1992)
      • https://doi.org/10.1119/1.17119
      • The richness of the solar spectrum at visible wavelengths makes it ideally suited for many laboratory exercises in optical spectroscopy. A number of such experiments taking advantage of a high‐resolution scanning spectrometer are described as they have been performed by seniors at Middlebury College. Physical principles emphasized include optical depth, the nature of molecular spectra, the Doppler effect, and the Zeeman effect. These experiments are suitable for advanced undergraduate physics and astronomy majors.
    • A rooftop radio observatory: An undergraduate telescope system at the University of California at Berkeley

      • Parthasarathy, R.; Frank, C.; Treffers, R.; Cudaback, D.; Heiles, C.; Hancox, C.; Millan, R., Am. J. Phys. 66, 768-771 (1998)
      • https://doi.org/10.1119/1.18956
      • We describe the 1- to 2-GHz radio telescope built by undergraduates with faculty guidance at the University of California at Berkeley. The telescope is optimized to observe the 1420-MHz (21-cm) emission line of neutral atomic hydrogen and is used in the recently created advanced undergraduate radio astronomy laboratory course, as well as in part of a graduate course on astronomical observation. We discuss the design of the telescope and the structure of the course and also present astronomical observations made with the telescope.
    • Isotope/element fractionation during surface adsorption

      • Seneviratne, Gamini; Nanayakkara, Asiri, Am. J. Phys. 72, 73-75 (2004)
      • https://doi.org/10.1119/1.1596177
      • The adsorption of ions onto mineral surfaces accompanies isotope/element fractionation in planets and asteroids. A model based on simple classical physics is presented to predict these fractionations. The agreement between the experimentally observed isotope/element ratios and their predicted values is found to be excellent. This fractionation can be demonstrated experimentally in advanced physics laboratories using macroscopic particles. The success of the model shows students that even a very complex naturally occurring process can be explained quantitatively with simple physics.
    • Measurement of the Earth’s rotational speed via Doppler shift of solar absorption lines

      • Oostra, Benjamin, Am. J. Phys. 80, 363-366 (2012)
      • https://doi.org/10.1119/1.3684841
      • This paper describes an experiment regularly presented to advanced undergraduate Physics students at the Universidad de los Andes in Bogotá, Colombia. The purpose of the experiment is to use high-resolution solar spectra to measure the horizontal speed of the laboratory caused by terrestrial rotation. Using this result, the radius of the Earth can be deduced. It is also possible to observe the Earth’s motion towards or away from the Sun, and hence compute our planet’s orbital eccentricity.
    • LIGO analogy lab—A set of undergraduate lab experiments to demonstrate some principles of gravitational wave detection

      • Ugolini, Dennis; Rafferty, Hanna; Winter, Max; Rockstuhl, Carsten; Bergmann, Antje, Am. J. Phys. 87, 44-56 (2019)
      • https://doi.org/10.1119/1.5066567
      • The first direct detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in September 2015 proved their existence, as predicted by Einstein's General Theory of Relativity, and ushered in the era of gravitational-wave interferometry. In this article, we present a set of lab course experiments at different levels of advancement, which give students insight into the basic LIGO operating principle and advanced detection techniques. Starting with methods for folding an optical cavity, we advance to analogy experiments with sound waves that can be detected with a Michelson interferometer with an optical cavity arm. In that experiment, students also learn how the sensitivity of the device can be tuned. In a last step, we show how optical heterodyne detection (the mixing of a signal with a reference oscillator) was used in Initial LIGO. We hope these experiments not only give students an understanding of some LIGO techniques but also awaken a fascination for how unimaginably tiny signals, created by powerful cosmic events a billion years ago or earlier, can be detected today here on Earth.
    • Continuous gravitational waves in the lab: Recovering audio signals with a table-top optical microphone

      • Gardner, James W.; Middleton, Hannah; Liu, Changrong; Melatos, Andrew; Evans, Robin; Moran, William; Beniwal, Deeksha; Cao, Huy Tuong; Ingram, Craig; Brown, Daniel; Ng, Sebastian, Am. J. Phys. 90, 286-296 (2022)
      • https://doi.org/10.1119/10.0009409
      • Gravitational-wave observatories around the world are searching for continuous waves: persistent signals from sources, such as spinning neutron stars. These searches use sophisticated statistical techniques to look for weak signals in noisy data. In this paper, we demonstrate these techniques using a table-top model gravitational-wave detector: a Michelson interferometer where sound is used as an analog for gravitational waves. Using signal processing techniques from continuous-wave searches, we demonstrate the recovery of tones with constant and wandering frequencies. We also explore the use of the interferometer as a teaching tool for educators in physics and electrical engineering by using it as an “optical microphone” to capture music and speech. A range of filtering techniques used to recover signals from noisy data are detailed in the supplementary material of this article. Here, we present the highlights of our results using a combined notch plus Wiener filter and the statistical log minimum mean-square error (logMMSE) estimator. Using these techniques, we easily recover recordings of simple chords and drums, but complex music and speech are more challenging. This demonstration can be used by educators in undergraduate laboratories and can be adapted for communicating gravitational-wave and signal-processing topics to nonspecialist audiences.
  • biophysics

    • A single molecule DNA flow stretching microscope for undergraduates

      • Williams, Kelly; Grafe, Brendan; Burke, Kathryn M.; Tanner, Nathan; van Oijen, Antoine M.; Loparo, Joseph; Price, Allen C., Am. J. Phys. 79, 1112-1120 (2011)
      • https://doi.org/10.1119/1.3620410
      • The design of a simple, safe, and inexpensive single molecule flow stretching instrument is presented. The instrument uses a low cost upright microscope coupled to a webcam for imaging single DNA molecules that are tethered in an easy to construct microfluidic flow cell. The system requires no special vibration isolation and is capable of measuring DNA replication at the single molecule level. We discuss two laboratory experiments suitable for advanced undergraduates using our microscope.
    • Inexpensive electronics and software for photon statistics and correlation spectroscopy

      • Gamari, Benjamin D.; Zhang, Dianwen; Buckman, Richard E.; Milas, Peker; Denker, John S.; Chen, Hui; Li, Hongmin; Goldner, Lori S., Am. J. Phys. 82, 712-722 (2014)
      • https://doi.org/10.1119/1.4869188
      • Single-molecule-sensitive microscopy and spectroscopy are transforming biophysics and materials science laboratories. Techniques such as fluorescence correlation spectroscopy (FCS) and single-molecule sensitive fluorescence resonance energy transfer (FRET) are now commonly available in research laboratories but are as yet infrequently available in teaching laboratories. We describe inexpensive electronics and open-source software that bridges this gap, making state-of-the-art research capabilities accessible to undergraduates interested in biophysics. We include a discussion of the intensity correlation function relevant to FCS and how it can be determined from photon arrival times. We demonstrate the system with a measurement of the hydrodynamic radius of a protein using FCS that is suitable for the undergraduate teaching laboratory. The FPGA-based electronics, which are easy to construct, are suitable for more advanced measurements as well, and several applications are described. As implemented, the system has 8 ns timing resolution, can control up to four laser sources, and can collect information from as many as four photon-counting detectors.
    • Lipid membranes and single ion channel recording for the advanced physics laboratory

      • Klapper, Yvonne; Nienhaus, Karin; Röcker, Carlheinz; Ulrich Nienhaus, G., Am. J. Phys. 82, 502-509 (2014)
      • https://doi.org/10.1119/1.4849815
      • We present an easy-to-handle, low-cost, and reliable setup to study various physical phenomena on a nanometer-thin lipid bilayer using the so-called black lipid membrane technique. The apparatus allows us to precisely measure optical and electrical properties of free-standing lipid membranes, to study the formation of single ion channels, and to gain detailed information on the ion conduction properties of these channels using statistical physics and autocorrelation analysis. The experiments are well suited as part of an advanced physics or biophysics laboratory course; they interconnect physics, chemistry, and biology and will be appealing to students of the natural sciences who are interested in quantitative experimentation.
    • Water network percolation on yeast as an experiment proposal for advanced physics laboratories for bioscience students

      • Dziob, Daniel; Sokołowska, Dagmara, Eur. J. Phys. 41, 25801 (2020)
      • https://dx.doi.org/10.1088/1361-6404/ab4ed2
      • Water is a crucial element of every living system, but its importance reaches further than biology. Thus, studying properties of water in different setups creates opportunities to bring together students of many disciplines. Here we propose a laboratory experiment on water network percolation in hydrated yeast, which enables description of the behavior of the water network surrounding living organisms during the dehydration process. Since the problem is interesting from a physical as well as biological point of view, the experiment can be introduced to student labs of both disciplines. In the experiment a simple RC circuit is used to observe 3D and 2D percolation phenomena in a sample of yeast. The parameters characterizing the phenomenon, such as percolation threshold and critical exponent, derived from the experimental data, provide information about the spatial organization of the water network surrounding yeast cells. The results obtained by four bioscience students using a simplified experimental setup are comparable with those presented in the literature and obtained by utilization of much more complex experimental methods.
  • chemical physics

    • Fluctuation correlation spectroscopy for the advanced physics laboratory

      • Rieger, Robert; Röcker, Carlheinz; Nienhaus, G. Ulrich, Am. J. Phys. 73, 1129-1134 (2005)
      • https://doi.org/10.1119/1.2074047
      • A fluorescence correlation spectrometer is developed that is suitable for use in advanced laboratory courses. The instrument is simple to build and understand and can be constructed at a small fraction of the cost of a commercial or research-grade instrument. We demonstrate its surprisingly high performance with a simple biophysics application, the study of the binding of two complementary DNA strands. The instrument will be useful in areas of physics where precise measurements of the dynamics of fluorescent (or fluorescently labeled) molecules or nanoparticles in solution are of interest.
  • condensed matter (other than solid state and fluids)

    • Second-Sound Experiment for Advanced Laboratories

      • Merrill, John R., Am. J. Phys. 36, 137-139 (1968)
      • https://doi.org/10.1119/1.1974440
      • This paper describes an advanced laboratory experiment concerning the propagation of second sound in liquid helium II. Both pulse propagation and standing-wave mode experiments are performed. Typical student data are presented. Both velocity and attenuation as functions of frequency and temperature are measured. Students' results agree well with published data. The student also learns how to handle liquid helium and its associated hardware.
    • Smartphone-based surface plasmon resonance imaging for near-field concentration mapping

      • Preechaburana, Pakorn; Amloy, Supaluck, Eur. J. Phys. 42, 45302 (2021)
      • https://dx.doi.org/10.1088/1361-6404/abf5ea
      • In this work, smartphone-based surface plasmon resonance imaging is used for the near-field mapping of a liquid sample’s concentration distribution. The principal design uses a special coupler based on a parallel incident light beam with p-polarization from a smartphone screen; this light is used to excite surface plasmons on a gold layer 50 nm thick. Using a bespoke application, surface plasmon resonance (SPR) intensity changes are detected in the SPR images captured with the front-facing camera. The SPR intensity is converted to the corresponding concentration using the three-layer Fresnel equation. Concentration mapping observations are presented for the dilution of ethanol dilution by water in a flow cell and an array of chlorine droplets on a gold surface. The high efficiency of this device means that it can be used for photonics research and advanced laboratory experiments.
  • electricity & magnetism

    • Ferroelectricity Experiment for Advanced Laboratory

      • Schmidt, V. Hugo, Am. J. Phys. 37, 351-354 (1969)
      • https://doi.org/10.1119/1.1975572
      • An experiment suitable for a junior or senior physics laboratory is described, in which the spontaneous polarization and coercive field for Rochelle salt are measured from the ferroelectric hysteresis loops, over the temperature range −18° to +24°C in which this crystal is ferroelectric. The suitability of triglycine sulfate for this experiment is discussed. The apparatus is also useful in demonstrating the relation of capacitance to electrode geometry, and in determining dielectric constants.
    • An advanced laboratory in nuclear-isotope mass spectroscopy

      • Shaheen, S. A.; Shapiro, M.; Becchetti, F. D., Am. J. Phys. 66, 1048-1055 (1998)
      • https://doi.org/10.1119/1.19044
      • We describe an experiment in nuclear-isotope mass spectroscopy, suitable for an advanced physics laboratory, which utilizes a relatively inexpensive commercial 60°-dipole residual gas analyzer. Students measure the terrestrial abundance of the isotope Ne22 relative to Ne20 and compare this with recent measurements of this ratio in meteorites. These ratios provide clues to the astrophysical sites, astrophysical processes, and nuclear reactions which formed these isotopes. The mass spectrometer is also used as a residual gas analyzer to examine the gas composition (O2, N2, H2O,…) at various pressures in a typical vacuum system. This gives students insight into the design of vacuum apparatus including the optimal selection of components such as vacuum pumps for particular applications.
    • “Franklin’s Bells” and charge transport as an undergraduate lab

      • Krotkov, R. V.; Tuominen, M. T.; Breuer, M. L., Am. J. Phys. 69, 50-55 (2001)
      • https://doi.org/10.1119/1.1313519
      • “Franklin’s Bells” is a popular lecture demonstration in electricity but seems to have been overlooked as a quantitative undergraduate lab experiment. In our version, a charged ball oscillates back and forth between the plates of a capacitor. This paper has two purposes: one is to discuss some of the wide variety of experiments and calculations which this system affords, the other is to present an analysis of a particular situation in which the ball excites resonant modes of the plates. This excitation gives rise to unexpected steps in the graph of shuttle frequency versus the potential difference between the plates. The apparatus required to show the demonstration is available in most physics departments. Similarly, a quantitative experiment for an introductory undergraduate lab does not require any unusual equipment, nor particularly high voltages. (In our experiment, the highest voltage used was 600 V; this can probably be reduced by scaling down the apparatus.) The physical situation may be analyzed at many different levels, suitable for students in the freshman to senior years, and ranging from a qualitative understanding of the demonstration to computer calculations of chaotic dynamics. The apparatus may be a simple one appropriate to the introductory level, or, at an “Advanced Lab” level, a sophisticated one, with computer-controlled measurements and analysis of various parameters. It is surprising that such a rich system has been neglected in the traditional curriculum.
    • How to detect buried structures through electrical measurements

      • Osella, A.; Chao, G.; Sánchez, F., Am. J. Phys. 69, 455-461 (2001)
      • https://doi.org/10.1119/1.1333100
      • The experiment reported here, performed by advanced undergraduates as a final laboratory work, was intended as an example of the application of the electricity theory to solve problems related to environmental physics. In particular, the aim of the work was to show how we can get the electrical image of the soil and detect the presence of buried structures from simple geoelectrical measurements. First, we developed scale models in the laboratory to recognize the electrical responses of different layered structures and to evaluate the sensitivity of the method and we interpreted the results using one-dimensional inversion codes. Then we proposed a configuration which permitted simulating a buried pipeline and analyzed the electrical response applying a simple two-dimensional numerical code. Finally, we performed field work in order to compare the results with ones obtained through the laboratory scale models. (C) 2001 American Association of Physics Teachers.
    • Force characterization of eddy currents

      • Pellicer-Porres, J.; Lacomba-Perales, R.; Ruiz-Fuertes, J.; Martínez-García, D.; Andrés, M. V., Am. J. Phys. 74, 267-271 (2006)
      • https://doi.org/10.1119/1.2178848
      • We discuss an experiment for an undergraduate laboratory designed to characterize eddy currents from the forces associated with them. Eddy currents also can be associated with the magnetization and described by a complex magnetic susceptibility. We establish an iterative method for calculating the magnetic susceptibility that is applicable to different geometries without using advanced mathematics. We apply our results to experiments with massive and hollow cylinders for which the susceptibility depends on the geometry. By measuring the force we obtain the cylinders’ conductivity with a contactless technique.
    • An experiment on the Rayleigh instability of charged liquid drops

      • Fong, Chee Sheng; Black, Nathan D.; Kiefer, Peter A.; Shaw, Raymond A., Am. J. Phys. 75, 499-503 (2007)
      • https://doi.org/10.1119/1.2717221
      • We describe a simple experiment to observe the fission of an electrically charged liquid droplet. Rayleigh charge instability occurs when the electrostatic repulsion of charges on the surface of a droplet overcomes the droplet surface tension and tears the droplet apart. The experiment requires a low-power laser, simple optics, a CCD camera, and a quadrupole trap, which can be constructed using widely available and relatively straightforward instructions. The experiment was performed primarily by undergraduates as part of their senior research projects and can be implemented readily in an advanced undergraduate physics laboratory course.
    • On thermionic emission and the use of vacuum tubes in the advanced physics laboratory

      • Angiolillo, Paul J., Am. J. Phys. 77, 1102-1106 (2009)
      • https://doi.org/10.1119/1.3212463
      • Two methods are outlined for measuring the charge-to-mass ratio e/me of the electron using thermionic emission as exploited in vacuum tube technology. One method employs the notion of the space charge in the vacuum tube diode as described by the Child–Langmuir equation; the other method uses the electron trajectories in vacuum tube pentodes with cylindrical electrodes under conditions of orthogonally related electric and magnetic fields (the Hull magnetron method). The vacuum diode method gave e/me=1.782±0.166×10+11 C/kg (averaged over the vacuum diodes studied), and the Hull magnetron method gave e/me=1.779±0.208×10+11 C/kg (averaged over both pentodes and the anode voltages studied). These methods afford opportunities for students to determine the e/me ratio without using the Bainbridge tube method and to become familiar with phenomena not normally covered in a typical experimental methods curriculum.
    • Comment on “On thermionic emission and the use of vacuum tubes in the advanced physics laboratory” by Paul J. Angiolillo [Am. J. Phys. 77 (12), 1102–1106 (2009)]

      • Polley, Patrick, Am. J. Phys. 78, 878 (2010)
      • https://doi.org/10.1119/1.3383928
      • The second point is that the information provided in Fig. 7 can be used to determine the energy distribution of the electrons. The author suggested a number of possible reasons for the sigmoid shape of the curves, but the most important factor is one that he neglected to mention and that is that there is a voltage drop along the filament. This voltage drop means that the electrons do not all have the same energy. The energy distribution of the electrons may be obtained by taking the derivative of the current with respect to the stopping potential provided by the magnetic field. The stopping potential may be calculated using the corrected Eq. (8) for each value of the magnetic field. The resulting current versus stopping potential graph is then fitted to a Lagrange interpolating polynomial. This polynomial is differentiated to provide the shape of the electron energy distribution. Applying this approach to the data in Fig. 7 suggests that the full width at half maximum of the electron energy distribution for each tube is approximately 10 V, which is consistent with the voltage supplied by a typical 6.3 V (rms) filament transformer.
    • Measuring the molecular polarizability of air

      • Madsen, M. J.; Brown, D. R.; Krutz, S. R.; Milliman, M. J., Am. J. Phys. 79, 428-430 (2011)
      • https://doi.org/10.1119/1.3533354
      • We present an update of the “refractive index of air” experiment, which is commonly used in undergraduate advanced laboratories. The refractive index of air depends on the average molecular polarizability, which can be determined from the period of the phase shift in a Michelson interferometer as a function of air pressure. The measured average molecular polarizability of air is γmol=(2.118±0.091)×10−29 m3 (95% CI). The corresponding refractive index of air at atmospheric pressure is n=1.000265(11), which agrees with the accepted value of n=1.000271375(6).
    • Electromagnetic wave velocities: an experimental approach

      • Santos, A. C. F.; Santos, W. S.; Aguiar, C. E., Eur. J. Phys. 34, 591 (2013)
      • https://dx.doi.org/10.1088/0143-0807/34/3/591
      • We describe experiments with coaxial transmission lines for the study of some of the velocities used to characterize the propagation of electromagnetic waves in a medium, namely phase, group and signal velocities. The experiments are suitable for undergraduates at advanced laboratory level. Their purpose is to acquaint the students with the fact that in a dispersive medium there are many possible definitions for the speed of light, and that the measurement of these different velocities is important for general understanding of wave propagation.
    • A low voltage "railgun"

      • Starr, Stanley O.; Youngquist, Robert C.; Cox, Robert B., Am. J. Phys. 81, 38-43 (2013)
      • https://doi.org/10.1119/1.4760659
      • Due to recent advances in solid-state switches and ultra-capacitors, it is now possible to construct a "railgun" that can operate at voltages below 20 V. Railguns typically operate above a thousand volts, generating huge currents for a few milliseconds to provide thousands of g's of acceleration to a small projectile. The low voltage railgun described herein operates for much longer time periods (tenths of seconds to seconds), has far smaller acceleration and speed, but can potentially propel a much larger object. The impetus for this development is to lay the groundwork for a possible ground-based supersonic launch track, but the resulting system may also have applications as a simple linear motor. The system would also be a useful teaching tool, requiring concepts from electrodynamics, mechanics, and electronics for its understanding, and is relatively straightforward to construct. (C) 2013 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4760659]
    • Developing a Kerr microscope for upper-division solid-state physics laboratories

      • Neff, David; Hoemke, Anatol; Attig, Adam R.; Cordova Mireles, Hector, Am. J. Phys. 82, 574-582 (2014)
      • https://doi.org/10.1119/1.4863916
      • We have constructed a low-cost Kerr microscope for use in our upper-division solid-state laboratory course by retrofitting a polarizing microscope. It was tested by imaging the magnetic domains on the surface of the polished ferromagnetic samples Nd-Fe-B and Fe-Si. The instrument serves as a learning platform for students who use it to study essential aspects of magnetic domains, as observed using the magneto-optic Kerr effect. By applying a controlled external magnetic field to a sample, magnetic domains can be observed and manipulated in real time with the aid of a digital camera. We offer technical guidance for the development of such a microscope and outline learning objectives for undergraduates in a formal lab curriculum.
    • A slowly rotating hollow sphere in a magnetic field: First steps to de-spin a space object

      • Youngquist, Robert C.; Nurge, Mark A.; Starr, Stanley O.; Leve, Frederick A.; Peck, Mason, Am. J. Phys. 84, 181-191 (2016)
      • https://doi.org/10.1119/1.4936633
      • Modeling the interaction of a slowly rotating hollow conducting sphere in a magnetic field provided an understanding of the dynamics of orbiting space objects moving through the Earth's magnetic field. This analysis, performed in the late 1950s and limited to uniform magnetic fields, was innovative and acknowledged the pioneers who first observed rotary magnetism, in particular, the seminal work of Hertz in 1880. Now, there is interest in using a magnetic field produced by one space object to stop the spin of a second object so that docking can occur. In this paper, we consider, yet again, the interaction of a rotating hollow sphere in a magnetic field. We show that the predicted results can be tested experimentally, making this an interesting advanced student project. This analysis also sheds light on a rich set of previously unaddressed behaviors involving eddy currents.
    • A thick-walled sphere rotating in a uniform magnetic field: The next step to de-spin a space object

      • Nurge, Mark A.; Youngquist, Robert C.; Caracciolo, Ryan A.; Peck, Mason; Leve, Frederick A., Am. J. Phys. 85, 596-610 (2017)
      • https://doi.org/10.1119/1.4984810
      • Modeling the interaction between a moving conductor and a static magnetic field is critical to understanding the operation of induction motors, eddy current braking, and the dynamics of satellites moving through Earth's magnetic field. Here, we develop the case of a thick-walled sphere rotating in a uniform magnetic field, which is the simplest, non-trivial, magneto-statics problem that leads to complete closed-form expressions for the resulting potentials, fields, and currents. This solution requires knowledge of all of Maxwell's time independent equations, scalar and vector potential equations, and the Lorentz force law. The paper presents four cases and their associated experimental results, making this topic appropriate for an advanced student lab project.
    • A modulation technique for the measurement of the DC longitudinal Faraday effect

      • Hunte, Carlos, Eur. J. Phys. 39, 25301 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aa9cbc
      • A modulation of light technique, using a lock-in amplifier, is described and tested to investigate the longitudinal Faraday effect in isotropic media. The Faraday rotation is measured directly from the lock-in amplifier. The Verdet constant and dispersion of lead-silica SF-59 Schott glass, at room temperature of 25 °C, were determined for varying wavelengths and expressions for their wavelength dependence were determined. The Verdet constant of water is also investigated. The results compare extremely well with other studies. The technique is suited to measure very small Verdet constants and can be easily conducted in an upper-level undergraduate laboratory.
    • Eddy currents in multilayer coils

      • Gorbatyy, Igor N.; Zhura, Iana P., Am. J. Phys. 89, 284-290 (2021)
      • https://doi.org/10.1119/10.0002444
      • This article considers an example of eddy current behaviour that has not been described previously in textbooks and physics education journals. This phenomenon involves a sharp rise in the active resistance of a multilayer coil with increasing alternating current frequency. This effect is not explained by the classic skin effect and is not related to losses in a core. The results of measurements of the frequency dependence of the active resistance of multilayer coils obtained by the resonance method and the results of calculating this dependence in the framework of the tape model of a multilayer solenoid are presented. The special case of relatively low frequencies is analysed when the classic skin effect is weak in a solitary wire. However, the active resistance of a multilayer coil is significantly higher than its DC resistance. A schematic model of the observed effect is proposed. The analysed example of eddy currents is easy to realize in an experiment and open to clear physical interpretation. It might be appropriate for students of various specialities to discuss this effect in intermediate or advanced physics laboratories.
    • Surface plasmon resonance sensing in the advanced physics laboratory

      • Abdelhamid, Alaa Adel; Kerrigan, David; Koopman, William; Werner, Andrew; Givens, Zachary; Donev, Eugenii U., Am. J. Phys. 90, 865-880 (2022)
      • https://doi.org/10.1119/5.0070022
      • We present a set of experiments and computations suitable for introducing upper-level undergraduate physics and engineering students to the interdisciplinary field of nanoplasmonics for periods ranging from a week-long advanced laboratory session to a summer research project. The end product is a tunable optofluidic device capable of detecting changes in a fluid medium as low as 0.002 refractive index units. The sensing element-a thin gold film on a glass prism coupled to a microfluidic cell-owes its sensitivity to the bound nature of the surface plasmon-polariton waves that are resonantly excited by evanescently coupled light at the gold-fluid interface. Pedagogically, surface plasmon resonance (SPR) sensing immerses students in the rich physics of nanoscale optics and evanescent waves in constructing and operating a precision apparatus and in developing theoretical, analytical, and numerical models to aid both in the physical understanding and engineering optimization of the SPR sensor. (c) 2022 Published under an exclusive license by American Association of Physics Teachers.
    • Theoretical and experimental examination of simple coaxial photonic crystals for undergraduate teaching

      • Guo, Xubo; Liu, Yingying; Chang, Ying; Zhu, Meihong; Zhang, Liuwan, Am. J. Phys. 90, 152-158 (2022)
      • https://doi.org/10.1119/5.0059320
      • A study implementing a coaxial photonic crystal with a simple structure composed of only one type of coaxial cable is described. The coaxial photonic crystal consists of alternating sections of a single cable and N parallel cables, with impedances of ZH and ZH/N, respectively. The high mismatch in impedance at the interfaces enables access to a highly superluminal group velocity with few cables. An easily realizable method is also presented to measure both the amplitude of transmission and the phase of the crystal by using an oscilloscope and a function generator. The measurements were validated by an advanced vector network analyzer and matched the results of theoretical analysis based on the transfer matrix method. The experiment only requires electronic components and equipment that are typically used in undergraduate teaching laboratories.
    • An economical smoke chamber and light-sheet microscope system for experiments in fluid dynamics and electrostatics

      • Stephan, Karl D., Am. J. Phys. 91, 316 (2023)
      • https://doi.org/10.1119/5.0122766
      • A smoke chamber and light-sheet video microscope setup is relatively easy to construct and provides opportunities for undergraduates to participate in a variety of advanced experiments, including the demonstration of Brownian motion and the interaction of induced electrostatic dipoles in aerosol particle agglomeration. We present results of these experiments along with information to allow replication of the setup in undergraduate physics laboratories. A theoretical model of the rate of aerosol agglomeration of long dipole chains as a function of electric field agrees with experiments at field strengths up to 200 kV m−1.
  • electronics

    • Frequency‐domain description of a lock‐in amplifier

      • Scofield, John H., Am. J. Phys. 62, 129-133 (1994)
      • https://doi.org/10.1119/1.17629
      • The basic principles behind the operation of a lock‐in amplifier are described. Particular emphasis is placed on looking at the frequency components of the signal present at the various stages of the lock‐in during a typical measurement. The description presented here has been used successfully to explain lock‐in operation to upper‐level laboratory students at Oberlin College.
    • Mutual entrainment of two nonlinear oscillators

      • Heath, T.; Wiesenfeld, K., Am. J. Phys. 66, 860-866 (1998)
      • https://doi.org/10.1119/1.18984
      • We present an example of how two nonidentical oscillators can synchronize due to dynamical nonlinear interactions. This highlights a classic distinction with coupled linear oscillators, a difference which is important to the functioning of several systems in physics and biology. We illustrate the phenomenon using an electronic circuit appropriate for an advanced undergraduate physics lab.
    • A compact apparatus for muon lifetime measurement and time dilation demonstration in the undergraduate laboratory

      • Coan, Thomas; Liu, Tiankuan; Ye, Jingbo, Am. J. Phys. 74, 161-164 (2006)
      • https://doi.org/10.1119/1.2135319
      • We describe a compact apparatus for measuring the charge-averaged lifetime of atmospheric muons in plastic scintillator using low-cost, low-power electronics. We present measurements of the stopping rate of atmospheric muons as a function of altitude to demonstrate relativistic time dilation. The apparatus is designed for the advanced undergraduate physics laboratory and is suitable for field measurements.
    • Nonlinear damping of the LC circuit using antiparallel diodes

      • Hellen, Edward H.; Lanctot, Matthew J., Am. J. Phys. 75, 326-330 (2007)
      • https://doi.org/10.1119/1.2710481
      • We investigate a simple variation of the series RLC circuit in which antiparallel diodes replace the resistor. The result is a damped harmonic oscillator with a nonlinear damping term that is a maximum at zero current and decreases inversely with the current for currents far from zero. Unlike the standard RLC circuit, the behavior of this circuit is amplitude dependent. The transient response makes a transition from underdamped to overdamped behavior, and the resonance response of the steady-state driven oscillator becomes sharper as the source amplitude increases. A set of nonlinear differential equations is derived for the circuit and integrated numerically for comparison with measurements. The equipment is inexpensive and common to upper level physics labs.
    • Modeling excitable systems: Reentrant tachycardia

      • Lancaster, Jarrett L.; Hellen, Edward H.; Leise, Esther M., Am. J. Phys. 78, 56-63 (2010)
      • https://doi.org/10.1119/1.3246868
      • Excitable membranes are an important type of nonlinear dynamical system, and their study can be used to provide a connection between physical and biological circuits. We discuss two models of excitable membranes important in cardiac and neural tissues. One model is based on the Fitzhugh–Nagumo equations, and the other is based on a three-transistor excitable circuit. We construct a circuit that simulates reentrant tachycardia and its treatment by surgical ablation. This project is appropriate for advanced undergraduates as a laboratory capstone project or as a senior thesis or honors project and can also be a collaborative project, with one student responsible for the computational predictions and another for the circuit construction and measurements.
    • A low voltage "railgun"

      • Starr, Stanley O.; Youngquist, Robert C.; Cox, Robert B., Am. J. Phys. 81, 38-43 (2013)
      • https://doi.org/10.1119/1.4760659
      • Due to recent advances in solid-state switches and ultra-capacitors, it is now possible to construct a "railgun" that can operate at voltages below 20 V. Railguns typically operate above a thousand volts, generating huge currents for a few milliseconds to provide thousands of g's of acceleration to a small projectile. The low voltage railgun described herein operates for much longer time periods (tenths of seconds to seconds), has far smaller acceleration and speed, but can potentially propel a much larger object. The impetus for this development is to lay the groundwork for a possible ground-based supersonic launch track, but the resulting system may also have applications as a simple linear motor. The system would also be a useful teaching tool, requiring concepts from electrodynamics, mechanics, and electronics for its understanding, and is relatively straightforward to construct. (C) 2013 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4760659]
    • Investigating student understanding of operational-amplifier circuits

      • Papanikolaou, Christos P.; Tombras, George S.; Van De Bogart, Kevin L.; Stetzer, MacKenzie R., Am. J. Phys. 83, 1039-1050 (2015)
      • https://doi.org/10.1119/1.4934600
      • The research reported in this article represents a systematic, multi-year investigation of student understanding of the behavior of basic operational-amplifier (op-amp) circuits. The participants in this study were undergraduates enrolled in upper-division physics courses on analog electronics at three different institutions, as well as undergraduates in introductory and upper-division electrical engineering courses at one of the institutions. The findings indicate that many students complete these courses without developing a functional understanding of the behavior of op-amp circuits. This article describes the most prevalent conceptual and reasoning difficulties identified (typically after lecture and hands-on laboratory experience) as well as several implications for electronics instruction that have emerged from this investigation.
    • A versatile Lock-In digital Amplifier (LIdA): the case of mechanical resonances

      • Bessas, D.; Brück, E., Eur. J. Phys. 38, 35502 (2017)
      • https://dx.doi.org/10.1088/1361-6404/aa6606
      • The assembly of a Lock-In digital Amplifier (LIdA) from widely accessible ready-made modules is presented. This equipment, which does not require any advanced knowledge of electronics or programming, may introduce the experimenter to resonant techniques by registering mechanical resonances. The freely available control program allows for general data acquisition and further data processing. The apparatus is versatile and may corroborate the science and engineering laboratory in elasticity measurements or in a series of experiments where a modulated signal is a prerequisite.
    • Exploring delay dynamics with a programmable electronic delay circuit

      • Perez, Edgar; Werkheiser, Colleen; Striff, Alex; Illing, Lucas, Am. J. Phys. 88, 1006-1011 (2020)
      • https://doi.org/10.1119/10.0001695
      • Delay dynamics occur in a wide variety of natural and man-made systems. Even simple delay systems can generate complex dynamics whose exploration is rewarding. To allow such exploration as part of advanced undergraduate laboratory courses and be able to utilize systems that operate at convenient timescales, it is necessary to delay analog signals by several milliseconds. In this paper, we describe an implementation of a programmable digital circuit capable of delaying DC-coupled analog signals up to 262 ms at a 1 MHz sampling rate. The initial history of the system may also be arbitrarily programmed, enabling the study of transient behavior. As an application, we discuss the use of this programmable delay in a feedback circuit that produces period-four triangular solutions, in complete agreement with theoretical predictions.
    • A simple electronic circuit demonstrating Hopf bifurcation for an advanced undergraduate laboratory

      • Deo, Ishan; Khare, Krishnacharya, Am. J. Phys. 90, 908-913 (2022)
      • https://doi.org/10.1119/5.0062969
      • A nonlinear electronic circuit comprising of three nodes with a feedback loop is analyzed. The system has two stable states, a uniform state and a sinusoidal oscillating state, and it transitions from one to another by means of a Hopf bifurcation. The stability of this system is analyzed with nonlinear equations derived from a repressilator-like transistor circuit. The apparatus is simple and inexpensive, and the experiment demonstrates aspects of nonlinear dynamical systems in an advanced undergraduate laboratory setting.
    • Using lock-in detection to build a barcode scanner

      • Alexander, Riley E.; DiFrischia, Maya M.; Doubman, Margaret J.; Fabian Dubon, Stefany; Goltz, Lily; Li, Yuqian; Long, Rebecca A.; Love, Genevieve; Martinez Diers, Nina; Melpakkam, Matangi; Robinson, Catie; Tompkins, Elizabeth M.; Vanis, Avalon L. B.; Wang, Xinrui; Yu, Mallory; Spielman, Sarah E.; Noel, Michael W., Am. J. Phys. 91, 1023-1030 (2023)
      • https://doi.org/10.1119/5.0151621
      • Lock-in detection is a widely used experimental technique in which a weak signal is measured by modulating it at a particular frequency. Then, by detecting an experimental output at that frequency, the desired signal can be isolated from much larger-amplitude noise. Here, we report on the implementation and optimization of a homemade laser barcode scanner based on the lock-in technique. Our setup is comprised of components that are readily available in an undergraduate instructional laboratory. The successful transcription of the barcode into a digital signal was achieved, and this digital signal was collected with a simple computer and processed to reveal the encoded number.
    • Voltage decay in an RLC circuit is not what is taught: An advanced laboratory exercise

      • Kowalski, Frank V.; Swantek, Justin L.; D'Esposito, Tony; Brannum, Jacob, Am. J. Phys. 92, 186-188 (2024)
      • https://doi.org/10.1119/5.0068145
      • At first glance, a simple model of an RLC circuit taught in undergraduate courses provides a reasonable fit to experimental data. However, careful analysis demonstrates that this model does not accurately describe the behavior of the oscillations in this circuit and requires further refinement. Measuring and analyzing data from this system provides an opportunity for advanced lab students to engage in hypothesis construction, modeling, and experimental design as they seek to explain the discrepancy between these data and a model. The learning outcomes of this activity are consistent with the AAPT guidelines on the undergraduate laboratory experience. Furthermore, such experimentation allows students to bridge the gap between classroom learning and the real world.
  • equipment (general)

    • Construction of an inexpensive copper heat-pipe oven

      • Grove, T. T.; Hockensmith, W. A.; Cheviron, N.; Grieser, W.; Dill, R.; Masters, M. F., Eur. J. Phys. 30, 1229 (2009)
      • https://dx.doi.org/10.1088/0143-0807/30/6/003
      • We present a new, low-cost method of building an all copper heat-pipe oven that increases the practicality of this device in advanced undergraduate instructional labs. The construction parts are available at local hardware and plumbing supply stores, and the assembly techniques employed are simple and require no machining.
    • The suitability of 3D printed plastic parts for laboratory use

      • Zwicker, Andrew P.; Bloom, Josh; Albertson, Robert; Gershman, Sophia, Am. J. Phys. 83, 281-285 (2015)
      • https://doi.org/10.1119/1.4900746
      • 3D printing has become popular for a variety of users, from home hobbyists to scientists and engineers interested in producing their own laboratory equipment. In order to determine the suitability of 3D printed parts for our plasma physics laboratory, we measured the accuracy, strength, vacuum compatibility, and electrical properties of pieces printed in plastic. The flexibility of rapidly creating custom parts has led to the 3D printer becoming an invaluable resource in our laboratory. The 3D printer is also suitable for producing equipment for advanced undergraduate laboratories. (C) 2014 American Association of Physics Teachers.
    • Making an efficient but cost-effective automated goniometric device for a light-scattering study

      • Deb, Dwaipayan, Eur. J. Phys. 42, 15303 (2020)
      • https://dx.doi.org/10.1088/1361-6404/abb713
      • A goniometer is an instrument which is frequently used in optics and other branches of physics. It enables the study of light scattered in various directions from a solid, liquid or powdered sample. The goniometric instruments that are already available on the market are designed for a specific purpose and are quite costly. Fully-computerized devices—which automatically acquire data and control the positions of the light source and detector—are even more expensive. In this work, the instrumentation of a self-fabricated, low cost, but fully computerized goniometric instrument designed for studying a light-scattering problem in planetary science is described in detail. This device uses Arduino microcontroller boards for acquiring data, and stepper motors are employed for automated control of the positions of the light source and detector. A low-cost but high-intensity laser diode was used as the light source, and a very sensitive photodiode integrated circuit was used as the light detector. This work has a pedagogical value in the sense that the reader will benefit from learning about the techniques used, the components and their calibration, the software, etc. More importantly, the cost-effectiveness of this work may be beneficial to many experimentalists and instrument designers working in this field, to control their project budgets.
  • fluids

    • Investigating vortical dipolar flows using particle image velocimetry: An experiment for the advanced undergraduate laboratory

      • Afanasyev, Yakov, Am. J. Phys. 70, 86-88 (2002)
      • https://doi.org/10.1119/1.1410952
      • This paper describes a laboratory experiment designed to study vortex dipoles, fascinating structures that occur in geophysical and industrial turbulent flows. A particle image velocimetry measurement system is used to measure the velocity and vorticity fields in the flow. The apparatus required for the experiment is inexpensive and easy to construct.
    • The approximate determination of the critical temperature of a liquid by measuring surface tension versus the temperature

      • Maroto, J. A.; Nieves, F. J. de las; Quesada-Pérez, M., Eur. J. Phys. 25, 297 (2004)
      • https://dx.doi.org/10.1088/0143-0807/25/2/016
      • A classical experience in a physics student laboratory is to determine the surface tension of a liquid versus the temperature and to check the linear appearance of the obtained graph. In this work we show a simple method to estimate the critical temperature of three liquids by using experimental data of surface tension at different temperatures. By a logarithm fitting between surface tension and temperature, the critical temperature can be determined and compared with data from the literature. For two liquids (butanol and nitrobenzene) the comparison is acceptable but the differences are too high for the third liquid (water). By discussing the results it seems to be clear that the difference between the critical temperature of the liquid and the maximum temperature of the surface tension measurements is the determining factor in obtaining acceptable results. From this study it is possible to obtain more information on the liquid characteristics from surface tension measurements that are currently carried out in a student laboratory. Besides, in this paper it is shown how to select the most suitable liquids which provide both acceptable values for the critical temperature and measurements of the surface tension at moderate temperatures. The complementary use of numerical methods permits us to offer a complete experience for the students with a simple laboratory experiment which we recommend for physics students in advanced university courses.
    • Finding viscosity of liquids from Brownian motion at students' laboratory

      • Greczyło, Tomasz; Dębowska, Ewa, Eur. J. Phys. 26, 827 (2005)
      • https://dx.doi.org/10.1088/0143-0807/26/5/015
      • Brownian motion appears to be a good subject for investigation at advanced students' laboratory [1]. The paper presents such an investigation carried out in Physics Laboratory II at the Institute of Experimental Physics of Wroclaw University. The experiment has been designed to find viscosity of liquids from Brownian motion phenomenon. Authors use modern technology that helps to proceed with measurements and makes the procedure less time and effort consuming. Discussion of the process of setting up the experiment and the results obtained for three different solutions of glycerin in water are presented. Advantages and disadvantages of the apparatus are pointed out along with descriptions of possible future uses.
    • A single molecule DNA flow stretching microscope for undergraduates

      • Williams, Kelly; Grafe, Brendan; Burke, Kathryn M.; Tanner, Nathan; van Oijen, Antoine M.; Loparo, Joseph; Price, Allen C., Am. J. Phys. 79, 1112-1120 (2011)
      • https://doi.org/10.1119/1.3620410
      • The design of a simple, safe, and inexpensive single molecule flow stretching instrument is presented. The instrument uses a low cost upright microscope coupled to a webcam for imaging single DNA molecules that are tethered in an easy to construct microfluidic flow cell. The system requires no special vibration isolation and is capable of measuring DNA replication at the single molecule level. We discuss two laboratory experiments suitable for advanced undergraduates using our microscope.
    • Patterns beyond Faraday waves: observation of parametric crossover from Faraday instabilities to the formation of vortex lattices in open dual fluid strata

      • Ohlin, Kjell; Berggren, Karl Fredrik, Eur. J. Phys. 37, 45803 (2016)
      • https://dx.doi.org/10.1088/0143-0807/37/4/045803
      • Faraday first characterised the behaviour of a fluid in a container subjected to vertical periodic oscillations. His study pertaining to hydrodynamic instability, the ‘Faraday instability’, has catalysed a myriad of experimental, theoretical, and numerical studies shedding light on the mechanisms responsible for the transition of a system at rest to a new state of well-ordered vibrational patterns at fixed frequencies. Here we study dual strata in a shallow vessel containing distilled water and high-viscosity lubrication oil on top of it. At elevated driving power, beyond the Faraday instability, the top stratum is found to ‘freeze’ into a rigid pattern with maxima and minima. At the same time there is a dynamic crossover into a new state in the form of a lattice of recirculating vortices in the lower layer containing the water. Instrumentation and the physics behind are analysed in a phenomenological way together with a basic heuristic modelling of the wave field. The study, which is based on relatively low-budget equipment, stems from related art projects that have evolved over the years. The study is of value within basic research as well as in education, especially as more advanced collective project work in e.g. engineering physics, where it invites further studies of pattern formation, the emergence of vortex lattices and complexity.
    • Inexpensive Mie scattering experiment for the classroom manufactured by 3D printing

      • Scholz, Christian; Sack, Achim; Heckel, Michael; Pöschel, Thorsten, Eur. J. Phys. 37, 55305 (2016)
      • https://dx.doi.org/10.1088/0143-0807/37/5/055305
      • Scattering experiments are fundamental for structure analysis of matter on molecular, atomic and sub-atomic length scales. In contrast, it is not standard to demonstrate optical scattering experiments on the undergraduate level beyond simple diffraction gratings. We present an inexpensive Mie scattering setup manufactured with 3D printing and open hardware. The experiment can be used to determine the particle size in dilute monodisperse colloidal suspensions with surprisingly high accuracy and is, thus, suitable to demonstrate relations between scattering measurements and microscopic properties of particles within undergraduate lab course projects.
    • The physics of water droplets on surfaces: exploring the effects of roughness and surface chemistry

      • Eid, K. F.; Panth, M.; Sommers, A. D., Eur. J. Phys. 39, 25804 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aa9cba
      • This paper explores the fluid property commonly called surface tension, its effect on droplet shape and contact angle, and the major influences of contact angle behaviour (i.e. surface roughness and surface chemistry). Images of water droplets placed on treated copper surfaces are used to measure the contact angles between the droplets and the surface. The surface wettability is manipulated either by growing a self-assembled monolayer on the surface to make it hydrophobic or by changing the surface roughness. The main activities in this experiment, then, are (1) preparing and studying surfaces with different surface wettability and roughness; (2) determining the shape and contact angles of water droplets on these surfaces; and (3) demonstrating the spontaneous motion of water droplets using surface tension gradients.
    • Fabrication and characterization of a microfluidic flow cytometer for the advanced undergraduate laboratory

      • Gorelik, Daniel; Alam, Faiyza; Milstein, Joshua N.; Piunno, Paul A. E., Am. J. Phys. 87, 214-222 (2019)
      • https://doi.org/10.1119/1.5084554
      • Microfluidic devices can be used to explore a vast range of phenomena in biophysics and soft-matter physics. While the popularity of these devices is in part driven by the ease of soft-lithography, most research labs still depend upon expensive, clean-room fabrication of photoresist molds, which can make this technique inaccessible to the undergraduate laboratory. However, there are much simpler, if coarser, approaches to designing molds that are capable of producing surprisingly complicated devices. Here, we detail the fabrication and characterization of a microfluidic device for flow cytometry or particle sorting on a chip. Our device is a layered polydimethylsiloxane chip that uses a series of Quake valves to sort. The molds were fabricated on equipment accessible to most undergraduate labs. The techniques and physics we discuss in this manuscript can be employed to create an almost endless variety of devices for learning about complex fluid mechanics, mesoscopic, soft-matter, and biological physics. (C) 2019 American Association of Physics Teachers.
    • An economical smoke chamber and light-sheet microscope system for experiments in fluid dynamics and electrostatics

      • Stephan, Karl D., Am. J. Phys. 91, 316 (2023)
      • https://doi.org/10.1119/5.0122766
      • A smoke chamber and light-sheet video microscope setup is relatively easy to construct and provides opportunities for undergraduates to participate in a variety of advanced experiments, including the demonstration of Brownian motion and the interaction of induced electrostatic dipoles in aerosol particle agglomeration. We present results of these experiments along with information to allow replication of the setup in undergraduate physics laboratories. A theoretical model of the rate of aerosol agglomeration of long dipole chains as a function of electric field agrees with experiments at field strengths up to 200 kV m−1.
  • liquid crystals

    • Resource letter: LC‐1: Liquid crystals: Physics and applications

      • Ondris‐Crawford, Renate J.; Crawford, Gregory P.; Doane, J. William, Am. J. Phys. 63, 781-788 (1995)
      • https://doi.org/10.1119/1.17801
      • This Resource Letter provides a list of references on liquid crystalline materials emphasizing both their fundamental properties and their practical uses in flat‐panel displays and electro‐optic applications. We have labeled those articles that can be used by students with little or no physics background and no prior knowledge of liquid crystals with an E (elementary), those that require a physics background but can be read by undergraduates with an I (intermediate), and the articles geared towards graduate students and researchers in the field with an A (advanced).
    • The Fréedericksz transition in liquid crystals: An undergraduate experiment for the advanced laboratory

      • Moses, Thomas; Jensen, Brian, Am. J. Phys. 66, 49-56 (1998)
      • https://doi.org/10.1119/1.18807
      • The Fréedericksz transition is a magnetically induced reorientation of the molecules of a liquid crystal. We describe here an experimental investigation of the Fréedericksz effect in liquid crystals for the advanced undergraduate laboratory. Besides introducing students to the novel and fascinating liquid-crystalline state of matter, the experiment serves as a valuable introduction to light propagation in an optically anisotropic medium and to the use of the calculus of variations in a somewhat unusual context. All components for the experiments are readily available and inexpensive.
    • Magnetic birefringence in a liquid crystal: An experiment for the advanced undergraduate laboratory

      • Moses, Thomas; Durall, Brian; Frankowiak, Gregory, Am. J. Phys. 68, 248-253 (2000)
      • https://doi.org/10.1119/1.19417
      • We describe an experiment involving an exciting phenomenon in liquid crystals, the magnetic field induced birefringence. We present a theoretical description accessible to junior- or senior-level physics majors, and we describe experiments for measuring the field and temperature dependence of the magnetic birefringence. The apparatus required for the experiment is inexpensive and/or easily constructed.
  • magnetic resonance

    • Nuclear Magnetic Resonance as an Advanced Laboratory Experiment

      • Wangsness, Rk, Am. J. Phys. 18, 521-521 (1950)
      • none
      • nan
    • Advanced laboratory NMR spectrometer with applications

      • Biscegli, Clovis; Panepucci, Horacio; Farach, Horacio A.; Poole, Charles P., Jr., Am. J. Phys. 50, 48-50 (1982)
      • https://doi.org/10.1119/1.13005
      • A description is given of an inexpensive NMR spectrometer that is suitable for use in an advanced laboratory course. The application of this spectrometer to the measurement of the oil content in corn seeds and the role of polymerization are presented.
    • Observing hyperfine interactions of NV− centers in diamond in an advanced quantum teaching lab

      • Yang, Yang; Vallabhapurapu, Hyma H.; Sewani, Vikas K.; Isarov, Maya; Firgau, Hannes R.; Adambukulam, Chris; Johnson, Brett C.; Pla, Jarryd J.; Laucht, Arne, Am. J. Phys. 90, 550-560 (2022)
      • https://doi.org/10.1119/5.0075519
      • The negatively charged nitrogen-vacancy (NV−) center in diamond is a model quantum system for university teaching labs due to its room-temperature compatibility and cost-effective operation. Based on the low-cost experimental setup that we have developed and described for the coherent control of the electronic spin [Sewani et al., Am. J. Phys. 88, 1156–1169 (2020)], we introduce and explain here a number of more advanced experiments that probe the electron–nuclear interaction between the NV− electronic and the 14N and 13C nuclear spins. Optically detected magnetic resonance, Rabi oscillations, Ramsey fringe experiments, and Hahn echo sequences are implemented to demonstrate how the nuclear spins interact with the electron spins. Most experiments only require 15 min of measurement time and, therefore, can be completed within one teaching lab.
  • mechanical systems

    • Coupled Pendulums: An Advanced Laboratory Experiment

      • Olsen, Leonard O., Am. J. Phys. 13, 321-324 (1945)
      • https://doi.org/10.1119/1.1990738
      • nan
    • An Advanced Undergraduate Laboratory Experiment for Studying the Motion of Forced Vibration

      • Bueche, F.; Pavelka, C., Am. J. Phys. 32, 857-859 (1964)
      • https://doi.org/10.1119/1.1969921
      • An advanced undergraduate laboratory experiment which studies the response of a bar to forced transverse vibrations is described. The amplitude and phase of vibration are monitored using a relatively simple optical system involving Moire fringes. Light is passed through two Ronchi rulings onto a photocell, the photocell output being a direct measure of the phase and the amplitude of vibration. The photocell output and the oscillator voltage used to drive the bar can be applied to the vertical and horizontal input, respectively, of an oscilloscope to produce Lissajous figures. These figures can then be studied and related to the properties of forced vibration. Typical results for resonance curves with and without external damping are given.
    • Bifilar Pendulum—An Experimental Study for the Advanced Laboratory

      • Then, John W., Am. J. Phys. 33, 545-547 (1965)
      • https://doi.org/10.1119/1.1971900
      • This study is concerned with various forms of bifilar suspensions and a quantitative comparison of experiment with theory. The various forms of the equations and the surprisingly simple form taken by some are considered. Moments of inertia are obtained experimentally and compared with the calculated moments from the theory.
    • An upper division student laboratory experiment which measures the velocity dispersion and nonlinear properties of gravitational surface waves in water

      • Wu, Junru; Rudnick, Isadore, Am. J. Phys. 52, 1008-1010 (1984)
      • https://doi.org/10.1119/1.13776
      • An undergraduate experiment designed to study the dispersion relation and nonlinearity of surface water waves in a trough is discussed. For small amplitudes a resonance technique is used to determine the wave velocity at the frequencies of the lowest modes of the trough. For the finite amplitude case, there is subharmonic nonlinear response for the plane wave mode propagating along the trough’s length as well as waves which reflect from the trough’s sides.
    • Experimental determination of normal frequencies in coupled mechanical oscillator systems using fast Fourier transforms: An advanced undergraduate laboratory

      • Weigman, Bernard J.; Perry, Helene F., Am. J. Phys. 61, 1022-1027 (1993)
      • https://doi.org/10.1119/1.17385
      • An experimental method for determining frequencies present in complex oscillating systems is given. When an oscillating system is attached to a force transducer, the time‐varying force is converted to a voltage. Using an analog to digital converter, a PC/XT samples 1024 points. A fast Fourier transform is performed which gives the frequency or frequencies present in the signal. Results are reported for several coupled systems of mass and spring combinations. In each case the experimentally measured frequencies agree to within 1% of the theoretically calculated values.
    • Nonlinear coupled oscillators and Fourier transforms: An advanced undergraduate laboratory

      • DeYoung, P. A.; LaPointe, D.; Levy, J.; Lorenz, W., Am. J. Phys. 64, 898-902 (1996)
      • https://doi.org/10.1119/1.18118
      • As part of an upper‐level laboratory course, the oscillations of one and two mass systems on an airtrack were measured in real time. Both linear oscillations with spring forces and nonlinear oscillations with magnetic forces were analyzed with fast Fourier transforms and compared to theoretical predictions. The results for the coupled linear oscillator agree with the theoretical values to within 0.5%. The coupled nonlinear oscillator results were modeled numerically.
    • Nonlinear dynamics of a sinusoidally driven pendulum in a repulsive magnetic field

      • Siahmakoun, Azad; French, Valentina; Patterson, Jeffrey, Am. J. Phys. 65, 393-400 (1997)
      • https:://doi.org/10.1119/1.18546
      • The dynamics of a sinusoidally driven pendulum in a repulsive magnetic field is investigated theoretically and experimentally. The experimental data are acquired using a shaft encoder interfaced to a PC which measures the angular displacement of the pendulum as a function of time. Both the theoretical simulations and the experimental measurements exhibit regions of periodic and chaotic behavior, depending on the system parameters. Amplitude jumps, hysteresis, and bistable states are also observed. The simplicity of the apparatus makes this experiment suitable for an advanced undergraduate laboratory.
    • Isotope/element fractionation during surface adsorption

      • Seneviratne, Gamini; Nanayakkara, Asiri, Am. J. Phys. 72, 73-75 (2004)
      • https://doi.org/10.1119/1.1596177
      • The adsorption of ions onto mineral surfaces accompanies isotope/element fractionation in planets and asteroids. A model based on simple classical physics is presented to predict these fractionations. The agreement between the experimentally observed isotope/element ratios and their predicted values is found to be excellent. This fractionation can be demonstrated experimentally in advanced physics laboratories using macroscopic particles. The success of the model shows students that even a very complex naturally occurring process can be explained quantitatively with simple physics.
    • Analysis of the linearity of half periods of the Lorentz pendulum

      • Wickramasinghe, T.; Ochoa, R., Am. J. Phys. 73, 442-445 (2005)
      • https://doi.org/10.1119/1.1848113
      • We analyze the motion of the Lorentz pendulum, a simple pendulum whose length is changed at a constant rate k. We show both analytically and numerically that the half period Tn, the time between half oscillations as measured from midpoint to midpoint, increases linearly with the oscillation number n such that Tn+1−Tn≈kπ2/2g, where g is the acceleration due to gravity. A video camera is used to record the motion of the oscillating bob of the pendulum and verify the linearity of Tn with oscillation number. The theory and the experiment are suitable for an advanced undergraduate laboratory.
    • The macroscopic model of an atomic force microscope in the students' laboratory

      • Greczyło, Tomasz; Debowska, Ewa, Eur. J. Phys. 27, 501 (2006)
      • https://dx.doi.org/10.1088/0143-0807/27/3/004
      • This paper presents a macroscopic model of an atomic force microscope. The tool is designed for an advanced physics experiment to be carried out in Physics Laboratory II at the Institute of Experimental Physics, Wroclaw University. We discuss the process of setting up the experiment and the results of measurements of the model's characteristics. The image of a model surface topography realized with the apparatus is also presented. The advantages and disadvantages of the apparatus are discussed along with descriptions of its possible future uses.
    • The weight of a falling chain, revisited

      • Hamm, Eugenio; Géminard, Jean-Christophe, Am. J. Phys. 78, 828-833 (2010)
      • https://doi.org/10.1119/1.3429983
      • A vertically hanging chain is released from rest and falls due to gravity on a scale pan. We discuss the various experimental and theoretical aspects of this classic problem. Careful time-resolved force measurements allow us to determine the differences between the idealized problem and its implementation in the laboratory. We observe that, in spite of the upward force exerted by the pan on the chain, the free end at the top falls faster than a freely falling body. Because a real chain exhibits a finite minimum radius of curvature, the contact at the bottom results in a tensional force, which pulls the falling part downward.
    • Supercritical bifurcation in a simple mechanical system: An undergraduate experiment

      • Sharpe, J. P.; Sungar, N., Am. J. Phys. 78, 520-523 (2010)
      • https://doi.org/10.1119/1.3268758
      • An inverted pendulum is used to demonstrate a supercritical bifurcation. The results can be explained by a simple theory, and the apparatus is inexpensive, uses readily available USB cameras, and requires no machining. The experiment and analysis are suitable for an upper division advanced laboratory or as a demonstration in mechanics or nonlinear dynamics classes.
    • Video-based spatial portraits of a nonlinear vibrating string

      • Hassan, Umer; Usman, Zubair; Sabieh Anwar, Muhammad, Am. J. Phys. 80, 862-869 (2012)
      • https://doi.org/10.1119/1.4740251
      • The article describes a systematic experimental study of a string vibrating nonlinearly. The string is tracked in real time using strategically located cameras; the video tracking enables a remote observation of the oscillator without perturbing its inherent nonlinearities. We show that our technique can help probe the parametrically excited oscillations and study phenomena such as elliptical and circular trajectories near resonance, resonance fold-over, jump, hysteresis, and subharmonic resonance. The experiment has been successfully employed in the advanced physics laboratory.
    • Measurement of elastic modulus and ultrasonic wave velocity by piezoelectric resonator

      • Erhart, Jiří, Eur. J. Phys. 36, 15017 (2014)
      • https://dx.doi.org/10.1088/0143-0807/36/1/015017
      • A piezoelectric ceramic resonator is used for the ‘electrical’ measurement of elastic properties, i.e. Young’s modulus and ultrasonic wave velocity in metallic materials. Piezoelectric response is precisely calculated for the piezoelectric ceramic ring fixed at the end of a metallic rod. The piezoelectric ring serves as both an actuator as well as a sensor. The experimental setup and method of measurement using higher overtones is explained in detail and practically demonstrated for a set of different metallic materials. Young’s moduli and ultrasonic wave velocities are measured within 3% relative error. The presented method is suitable for an advanced engineering class or physics laboratory training.
    • Interdisciplinary cantilever physics: Elasticity of carrot, celery, and plasticware

      • Pestka, Kenneth A., II, Am. J. Phys. 82, 484-489 (2014)
      • https://doi.org/10.1119/1.4826190
      • This article presents several simple cantilever-based experiments using common household items (celery, carrot, and a plastic spoon) that are appropriate for introductory undergraduate laboratories or independent student projects. By applying Hooke's law and Euler beam theory, students are able to determine Young's modulus, fracture stress, yield stress, strain energy, and sound speed of these apparently disparate materials. In addition, a cellular foam elastic model is introduced—applicable to biologic materials as well as an essential component in the development of advanced engineering composites—that provides a mechanism to determine Young's modulus of the cell wall material found in celery and carrot. These experiments are designed to promote exploration of the similarities and differences between common inorganic and organic materials, fill a void in the typical undergraduate curriculum, and provide a foundation for more advanced material science pursuits within biology, botany, and food science as well as physics and engineering.
    • Measuring nonlinear oscillations using a very accurate and low-cost linear optical position transducer

      • Donoso, Guillermo; Ladera, Celso L., Eur. J. Phys. 37, 55301 (2016)
      • https://dx.doi.org/10.1088/0143-0807/37/5/055301
      • An accurate linear optical displacement transducer of about 0.2 mm resolution over a range of ∼40 mm is presented. This device consists of a stack of thin cellulose acetate strips, each strip longitudinally slid ∼0.5 mm over the precedent one so that one end of the stack becomes a stepped wedge of constant step. A narrowed light beam from a white LED orthogonally incident crosses the wedge at a known point, the transmitted intensity being detected with a phototransistor whose emitter is connected to a diode. We present the interesting analytical proof that the voltage across the diode is linearly dependent upon the ordinate of the point where the light beam falls on the wedge, as well as the experimental validation of such a theoretical proof. Applications to nonlinear oscillations are then presented—including the interesting case of a body moving under dry friction, and the more advanced case of an oscillator in a quartic energy potential—whose time-varying positions were accurately measured with our transducer. Our sensing device can resolve the dynamics of an object attached to it with great accuracy and precision at a cost considerably less than that of a linear neutral density wedge. The technique used to assemble the wedge of acetate strips is described.
    • A versatile Lock-In digital Amplifier (LIdA): the case of mechanical resonances

      • Bessas, D.; Brück, E., Eur. J. Phys. 38, 35502 (2017)
      • https://dx.doi.org/10.1088/1361-6404/aa6606
      • The assembly of a Lock-In digital Amplifier (LIdA) from widely accessible ready-made modules is presented. This equipment, which does not require any advanced knowledge of electronics or programming, may introduce the experimenter to resonant techniques by registering mechanical resonances. The freely available control program allows for general data acquisition and further data processing. The apparatus is versatile and may corroborate the science and engineering laboratory in elasticity measurements or in a series of experiments where a modulated signal is a prerequisite.
    • Study of geometric phase using classical coupled oscillators

      • Bhattacharjee, Sharba; Dey, Biprateep; Mohapatra, Ashok K., Eur. J. Phys. 39, 35404 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aaa8a2
      • We illustrate the geometric phase associated with the cyclic dynamics of a classical system of coupled oscillators. We use an analogy between a classical coupled oscillator and a two-state quantum mechanical system to represent the evolution of the oscillator on an equivalent Hilbert space, which may be represented as a trajectory on the surface of a sphere. The cyclic evolution of the system leads to a change in phase, which consists of a dynamic phase along with an additional phase shift dependent on the geometry of the evolution. A simple experiment suitable for advanced undergraduate students is designed to study the geometric phase incurred during cyclic evolution of a coupled oscillator.
    • A parametric oscillator for classroom demonstration or student laboratory

      • Huff, Alison; Thompson, Johnathon; Pate, Jacob; Chiao, Raymond; Sharping, Jay E., Eur. J. Phys. 40, 65006 (2019)
      • https://dx.doi.org/10.1088/1361-6404/ab2fe9
      • We describe a simple and intuitive parametric oscillator apparatus which is suitable for a classroom demonstration or an upper-division laboratory. In order to facilitate the incorporation of this apparatus into the physics curriculum, we provide the learning objectives for an upper-division physics laboratory experiment. We present typical experimental data illustrating the main features of parametric oscillators including oscillation threshold, frequency shifting at large amplitude and bistability. Our experiments and theory emphasize identifying the lowest-order threshold for oscillation in terms of the modulation depth and quality factor. This experiment provides a foundation for understanding current research such as that in quantum opto-mechanics and nonlinear dynamics.
    • Gravity-driven fluid oscillations in a drinking straw

      • Smith, Ryan P.; Matlis, Eric H., Am. J. Phys. 87, 433-435 (2019)
      • https://doi.org/10.1119/1.5095945
      • We describe a simple experiment observing oscillations of fluid in a drinking straw immersed in a bath of water. The motion of this oscillator system with changing mass is matched remarkably well by a model derived from Newton's laws with the inclusion of only a phenomenological damping coefficient. We compare the frequency of the oscillations to Hooke's law for small displacements and find 0.25% discrepancy. This experiment can be shown as a demonstration of oscillations of fluids, or it can be performed by students as a laboratory activity in upper-division undergraduate physics and engineering courses.
    • Inharmonicity in plucked guitar strings

      • Murray, Chris J.; Whitfield, Scott B., Am. J. Phys. 90, 487-493 (2022)
      • https://doi.org/10.1119/5.0064373
      • We have considered the vibration of various types of pinned guitar strings and have investigated the deviation of the partials from integer multiples of the string's fundamental vibration frequency. We measured the inharmonicity parameter B and compared it to a direct calculation based on a model equation. We generally found very good agreement between the two determinations of B for monofilament strings, but perhaps not surprisingly, we find rather poor agreement for wound strings. Furthermore, we show that the methodology used to carry out this experiment can easily serve as the basis for an upper division physics laboratory on physical acoustics including a more thorough investigation of the classical wave equation in a real-world application.
    • Rotational modes of a double conical pendulum

      • Cross, Rod, Eur. J. Phys. 44, 25004 (2023)
      • https://dx.doi.org/10.1088/1361-6404/acacd6
      • Theoretical and experimental results are presented for a double conical pendulum rotated at the top end in a circular path of radius r 0. The rotation modes are different from those with r 0 = 0 and depend on whether the two pendulum masses rotate in or out of phase with the upper end and with each other. The results extend those already described in the physics teaching literature for a single conical pendulum, would be suitable as a lecture demonstration or an undergraduate laboratory experiment, and are closely analogous to those for a chain that is rotated at its upper end.
    • Transition from bouncing to rolling on a horizontal surface

      • Cross, Rod, Am. J. Phys. 92, 571-575 (2024)
      • https://doi.org/10.1119/5.0160345
      • If a ball is incident obliquely on a horizontal surface and is allowed to bounce more than once, then it is likely to bounce many times before it starts rolling along the surface. The number of bounces before rolling commences depends on the initial vertical speed and the normal coefficient of restitution. The transition from bouncing to rolling is examined using a simple theoretical model and is compared with experimental data obtained by filming the process with a video camera. We find that the final rolling speed is proportional to the initial horizontal speed of the ball and depends on the initial ball spin, but is independent of the tangential coefficient of restitution. Representative videos for different balls are included as supplementary material, including a superball thrown with a backspin that creates a back and forth motion. Instructors could use the experiment and/or analysis for an advanced undergraduate lab or use a simplified observational exercise for non-majors.
  • medical physics

    • A simple medical physics experiment based on a laser pointer

      • Delaney, C.; Rodriguez, J., Am. J. Phys. 70, 1068-1070 (2002)
      • https://pubs.aip.org/aapt/ajp/article-abstract/70/10/1068/310594/A-simple-medical-physics-experiment-based-on-a?redirectedFrom=fulltext
      • Recent advances in medical physics have led to a proliferation of. medical diagnostic instrumentation, particularly in the area of medical imaging. The pervasiveness of this new technology in turn has promoted a growing interest among physics faculty and students in courses covering this material (Ref. 1). However, few physics departments have responded to this interest with the creation of undergraduate courses in medical physics due to staffing limitations or a lack of experience in this area of physics or both. Nevertheless it may be possible for those institutions unable to offer a full course in medical physics to provide at least a substantial hands-on experience in the form of an advanced laboratory experiment on a representative topic, if it can be implemented with relative ease. In this paper we describe such an experiment in medical imaging using readily available hardware that illustrates the concepts behind one of the most successful medical imaging modalities developed to date, namely computed tomography (CT) (Ref. 2). (C) 2002 American Association of Physics Teachers.
    • Modeling excitable systems: Reentrant tachycardia

      • Lancaster, Jarrett L.; Hellen, Edward H.; Leise, Esther M., Am. J. Phys. 78, 56-63 (2010)
      • https://doi.org/10.1119/1.3246868
      • Excitable membranes are an important type of nonlinear dynamical system, and their study can be used to provide a connection between physical and biological circuits. We discuss two models of excitable membranes important in cardiac and neural tissues. One model is based on the Fitzhugh–Nagumo equations, and the other is based on a three-transistor excitable circuit. We construct a circuit that simulates reentrant tachycardia and its treatment by surgical ablation. This project is appropriate for advanced undergraduates as a laboratory capstone project or as a senior thesis or honors project and can also be a collaborative project, with one student responsible for the computational predictions and another for the circuit construction and measurements.
    • Low-cost diffuse optical tomography for the classroom

      • Minagawa, Taisuke; Zirak, Peyman; Weigel, Udo M.; Kristoffersen, Anna K.; Mateos, Nicolas; Valencia, Alejandra; Durduran, Turgut, Am. J. Phys. 80, 876-881 (2012)
      • https://doi.org/10.1119/1.4739924
      • Diffuse optical tomography (DOT) is an emerging imaging modality with potential applications in oncology, neurology, and other clinical areas. It allows the non-invasive probing of the tissue function using relatively inexpensive and safe instrumentation. An educational laboratory setup of a DOT system could be used to demonstrate how photons propagate through tissues, basics of medical tomography, and the concepts of multiple scattering and absorption. Here, we report a DOT setup that could be introduced to the advanced undergraduate or early graduate curriculum using inexpensive and readily available tools. The basis of the system is the LEGO Mindstorms NXT platform which controls the light sources, the detectors (photo-diodes), a mechanical 2D scanning platform, and the data acquisition. A basic tomographic reconstruction is implemented in standard numerical software, and 3D images are reconstructed. The concept was tested and developed in an educational environment that involved a high-school student and a group of post-doctoral fellows.
  • nano/micro fabrication

    • A maskless photolithographic prototyping system using a low-cost consumer projector and a microscope

      • Musgraves, J. David; Close, Brett T.; Tanenbaum, David M., Am. J. Phys. 73, 980-984 (2005)
      • https://doi.org/10.1119/1.1924491
      • Lithographic processing has been the key technology responsible for the rapid advances in microelectronics, but is typically not accessible to undergraduates. We have developed a maskless photolithographic system that can be assembled from a consumer projector and a trinocular microscope. This system allows students to design and print custom patterns into photoresist in less than 30 min, without using a clean room, a mask facility, or a chrome-etch bath. Students can create and evaluate patterns, make changes to their design, or add additional layers of aligned patterns in a single laboratory session. The rapid turnaround time and low cost of ownership is useful for low-resolution (∼10 μm) prototyping. Photoresist is spun in a modified food processor and baked on a standard hot plate. Mating pieces were machined from aluminum. Only the digital light processing projector and food processor are modified, so the microscope, camera, and computer need not be dedicated to the system. The entire system can be assembled for less than $5000.
    • Fabrication and characterization of a microfluidic flow cytometer for the advanced undergraduate laboratory

      • Gorelik, Daniel; Alam, Faiyza; Milstein, Joshua N.; Piunno, Paul A. E., Am. J. Phys. 87, 214-222 (2019)
      • https://doi.org/10.1119/1.5084554
      • Microfluidic devices can be used to explore a vast range of phenomena in biophysics and soft-matter physics. While the popularity of these devices is in part driven by the ease of soft-lithography, most research labs still depend upon expensive, clean-room fabrication of photoresist molds, which can make this technique inaccessible to the undergraduate laboratory. However, there are much simpler, if coarser, approaches to designing molds that are capable of producing surprisingly complicated devices. Here, we detail the fabrication and characterization of a microfluidic device for flow cytometry or particle sorting on a chip. Our device is a layered polydimethylsiloxane chip that uses a series of Quake valves to sort. The molds were fabricated on equipment accessible to most undergraduate labs. The techniques and physics we discuss in this manuscript can be employed to create an almost endless variety of devices for learning about complex fluid mechanics, mesoscopic, soft-matter, and biological physics. (C) 2019 American Association of Physics Teachers.
  • non-linear physics

    • Nonlinear dynamics of a magnetically driven Duffing-type spring–magnet oscillator in the static magnetic field of a coil

      • Donoso, Guillermo; Ladera, Celso L., Eur. J. Phys. 33, 1473 (2012)
      • https://dx.doi.org/10.1088/0143-0807/33/6/1473
      • We study the nonlinear oscillations of a forced and weakly dissipative spring–magnet system moving in the magnetic fields of two fixed coaxial, hollow induction coils. As the first coil is excited with a dc current, both a linear and a cubic magnet-position dependent force appear on the magnet–spring system. The second coil, located below the first, excited with an ac current, provides the oscillating magnetic driving force on the system. From the magnet–coil interactions, we obtain, analytically, the nonlinear motion equation of the system, found to be a forced and damped cubic Duffing oscillator moving in a quartic potential. The relative strengths of the coefficients of the motion equation can be easily set by varying the coils’ dc and ac currents. We demonstrate, theoretically and experimentally, the nonlinear behaviour of this oscillator, including its oscillation modes and nonlinear resonances, the fold-over effect, the hysteresis and amplitude jumps, and its chaotic behaviour. It is an oscillating system suitable for teaching an advanced experiment in nonlinear dynamics both at senior undergraduate and graduate levels.
    • Anharmonic oscillations of a spring–magnet system inside a magnetic coil

      • Ladera, Celso L.; Donoso, Guillermo, Eur. J. Phys. 33, 1259 (2012)
      • https://dx.doi.org/10.1088/0143-0807/33/5/1259
      • We consider the nonlinear oscillations of a simple spring–magnet system that oscillates in the magnetic field of an inductive coil excited with a dc current. Using the relations for the interaction of a coil and a magnet we obtain the motion equation of the system. The relative strengths of the terms of this equation can be adjusted easily by varying the coil excitation current. Both the elastic constant and the shape of the potential energy function of the system can therefore be modified by varying that current. It is shown and demonstrated that this system is a case of anharmonic oscillations in a double-well potential. This nonlinear oscillator can be easily assembled with commonly available laboratory components, and monitored with a digital oscilloscope. Its simplicity is to be compared with the setups of many other nonlinear oscillators recently described. This oscillator is ideal for an advanced undergraduate laboratory experiment or for project work.
    • Patterns beyond Faraday waves: observation of parametric crossover from Faraday instabilities to the formation of vortex lattices in open dual fluid strata

      • Ohlin, Kjell; Berggren, Karl Fredrik, Eur. J. Phys. 37, 45803 (2016)
      • https://dx.doi.org/10.1088/0143-0807/37/4/045803
      • Faraday first characterised the behaviour of a fluid in a container subjected to vertical periodic oscillations. His study pertaining to hydrodynamic instability, the ‘Faraday instability’, has catalysed a myriad of experimental, theoretical, and numerical studies shedding light on the mechanisms responsible for the transition of a system at rest to a new state of well-ordered vibrational patterns at fixed frequencies. Here we study dual strata in a shallow vessel containing distilled water and high-viscosity lubrication oil on top of it. At elevated driving power, beyond the Faraday instability, the top stratum is found to ‘freeze’ into a rigid pattern with maxima and minima. At the same time there is a dynamic crossover into a new state in the form of a lattice of recirculating vortices in the lower layer containing the water. Instrumentation and the physics behind are analysed in a phenomenological way together with a basic heuristic modelling of the wave field. The study, which is based on relatively low-budget equipment, stems from related art projects that have evolved over the years. The study is of value within basic research as well as in education, especially as more advanced collective project work in e.g. engineering physics, where it invites further studies of pattern formation, the emergence of vortex lattices and complexity.
    • Water network percolation on yeast as an experiment proposal for advanced physics laboratories for bioscience students

      • Dziob, Daniel; Sokołowska, Dagmara, Eur. J. Phys. 41, 25801 (2020)
      • https://dx.doi.org/10.1088/1361-6404/ab4ed2
      • Water is a crucial element of every living system, but its importance reaches further than biology. Thus, studying properties of water in different setups creates opportunities to bring together students of many disciplines. Here we propose a laboratory experiment on water network percolation in hydrated yeast, which enables description of the behavior of the water network surrounding living organisms during the dehydration process. Since the problem is interesting from a physical as well as biological point of view, the experiment can be introduced to student labs of both disciplines. In the experiment a simple RC circuit is used to observe 3D and 2D percolation phenomena in a sample of yeast. The parameters characterizing the phenomenon, such as percolation threshold and critical exponent, derived from the experimental data, provide information about the spatial organization of the water network surrounding yeast cells. The results obtained by four bioscience students using a simplified experimental setup are comparable with those presented in the literature and obtained by utilization of much more complex experimental methods.
    • A practical lab on composite materials and sensors, enhanced with electrical percolation threshold theory

      • Rendevski, Stojan J.; Dyussenbekov, Anuar M.; Nurlanov, Farkhat N., Eur. J. Phys. 41, 55802 (2020)
      • https://dx.doi.org/10.1088/1361-6404/ab90dd
      • Composites based on candle wax and pencil graphite were fabricated with different concentrations of graphite in the range 0% w/w to 70% w/w. These composites were fabricated (‘ironed’) into a sandwich structure with kitchen aluminum foil serving as electrodes. The composites’ electrical resistance was measured and it was found that the composite with 15% w/w of graphite was the best choice for further investigation according to the percolation theory of electrical conductivity thresholds. The wax–graphite composites were subjected to impact forces from a basketball, measured by the school’s PASCO equipment. A calibration curve of the specific electrical resistance versus the force of impact was constructed. Following the standards of the International Basketball Federation (FIBA), the quality of the basketball was evaluated in terms of the bounce height of a free-falling ball and the force acting on the ball during the impact with the floor. The wax–graphite composite with a threshold concentration of 15% w/w graphite proved to be a sensitive sensor for measuring the impact force, even when small forces were under investigation. The project as presented here could be used as a laboratory topic for advanced level high school physics or undergraduate lab work in materials science or applied physics.
  • nuclear physics

    • Modified Version of the MIT Rutherford Scattering Apparatus for Use in Advanced Undergraduate Laboratories

      • Earl, James A., Am. J. Phys. 34, 483-488 (1966)
      • https://doi.org/10.1119/1.1973075
      • Modifications of the MIT Rutherford Scattering Apparatus (Apparatus Drawings Project No. 16) are described. These include (1) use of a self-contained circuit for amplifying, analyzing, and counting pulses from the scintillation detector and (2) interchangeable foil holders which aid in the determination of background effects and which permit studies of scattering from various foils to be made. A description of the experiment performed by students at the University of Minnesota is given.
    • Measurement of Neutron-Induced, Fission-Fragment Energy Spectra in the Advanced Laboratory

      • French, W. R., Jr.; Bunting, R. L., Am. J. Phys. 37, 637-645 (1969)
      • https://doi.org/10.1119/1.1975731
      • Fission experiments can be profitably performed in the Advanced Laboratory. Measurement of the fragment energy spectrum from a fissile source using a surface barrier detector demonstrates several characteristics of the fission process. Experimental difficulties in such measurements are discussed, and typical results are presented for neutron-induced fission with sources of natural uranium and those enriched in U235. Also shown are the results with the spontaneous fissile source Cf252.
    • Modified scattering geometry for advanced undergraduate laboratory experiment on the Compton effect

      • Cornell, David A., Am. J. Phys. 52, 282-283 (1984)
      • https://doi.org/10.1119/1.13716
      • nan
    • Unknown gamma emitter identification for an advanced physics laboratory class, or don’t throw away your old Sn‐113 source

      • Fiske, Thomas G.; Jadrich, James R.; Zender, Michael J., Am. J. Phys. 52, 76-77 (1984)
      • https://doi.org/10.1119/1.13826
      • nan
    • Application of high-purity germanium (HPGe) detector to advanced laboratory experiment on the Compton effect

      • Hieronymus, Seth A.; Lundquist, Loraine L.; Cornell, David A., Am. J. Phys. 66, 836 (1998)
      • https://doi.org/10.1119/1.18969
      • nan
    • 252Cf fission-neutron spectrum using a simplified time-of-flight setup: An advanced teaching laboratory experiment

      • Becchetti, F. D.; Febbraro, M.; Torres-Isea, R.; Ojaruega, M.; Baum, L., Am. J. Phys. 81, 112-119 (2013)
      • https://doi.org/10.1119/1.4769032
      • The removal of PuBe and AmBe neutron sources from many university teaching laboratories (due to heightened security issues) has often left a void in teaching various aspects of neutron physics. We have recently replaced such sources with sealed 252Cf oil-well logging sources (nominal 10–100 μCi), and developed several experiments using them as neutron sources. This includes a fission-neutron time-of-flight experiment using plastic scintillators, which utilizes the prompt γ rays emitted in 252Cf spontaneous fission as a fast timing start signal. The experiment can be performed with conventional nuclear instrumentation and a 1-D multi-channel pulse-height analyzer, available in most advanced teaching laboratories. Alternatively, a more sophisticated experiment using liquid scintillators and n/γ pulse-shape discrimination can be performed. Several other experiments using these neutron sources are also feasible. The experiments can introduce students to the problem of detecting the dark matter thought to dominate the universe and to the techniques used to detect contraband fissionable nuclear materials.
    • Comment on “252Cf fission-neutron spectrum using a simplified time-of-flight setup: An advanced teaching laboratory experiment” [Am. J. Phys. 81, 112–119 (2013)]

      • Becchetti, F. D., Am. J. Phys. 82, 706 (2014)
      • https://doi.org/10.1119/1.4876218
      • Figure 6 in our recent paper1 shows a slight excess in the high-energy neutrons measured from a sealed 252Cf well-logging source relative to the accepted 252Cf fission-neutron spectrum (Watt spectrum2). As indicated in the paper, the main decay branch of 252Cf is alpha-particle emission rather than spontaneous fission (SF). However, a colleague3 has pointed out that many of the 252Cf daughter nuclei also have SF branches in addition to their primary alpha-decay modes. Hence in older, depleted, sealed 252Cf sources, such as the one used in the paper, these daughters can contribute to the slight excess of high-energy neutrons observed. In addition, (α,n) reactions on the source containment shell from high-energy α decays also can be a possible source of such neutrons. Thus, the exact shape of the neutron spectrum measured will depend somewhat on the age and containment vessel of the 252Cf fission source, and students may not necessarily produce a Watt spectrum exactly.
    • Energy-resolved coincidence counting using an FPGA for nuclear lifetime experiments

      • Vretenar, Mario; Erceg, Nataša; Karuza, Marin, Am. J. Phys. 87, 997-1003 (2019)
      • https://doi.org/10.1119/1.5122744
      • With the increasing availability of single-board computers equipped with fast analog-to-digital converters based on field-programmable gate arrays (FPGA), researchers and educators gain access to relatively inexpensive hardware that can be programmed for advanced coincidence counting. We demonstrate this capability by developing software for a dual-channel open-source data acquisition platform, enabling it to perform energy- and time-resolved coincidence counting and testing our system using an 241Am source. Measuring the coincidence between alpha and gamma radiation allowed us to determine the half-life of the 237Np excited state. The obtained value of 67.7 ± 0.1 ns is compatible with the value cited in the literature. Furthermore, the use of digital signal processing enabled us to sort time-resolved counts by alpha and gamma energy, which resulted in additional information on the decay scheme. Correlation heatmaps between the two spectra were plotted and used to verify the decay scheme. The half-lives of the other features visible in the gamma spectrum were determined as well.
    • Applications of high-speed digital pulse acquisition and software-defined electronics (SDE) in advanced nuclear teaching laboratories

      • Becchetti, F. D.; Damron, N.; Torres-Isea, R. O., Am. J. Phys. 88, 70-80 (2020)
      • https://doi.org/10.1119/1.5125128
      • There is a new generation of high-speed programmable pulse digitizers available now from several vendors at modest cost. These digitizers in tandem with on-board or post-processing software combine to produce a Software-Defined Electronics (SDE) system that can be effectively used in several advanced physics teaching lab experiments. In particular, as we will demonstrate, they are particularly well suited for nuclear-physics related experiments, often replacing many analog electronics modules. Appropriate on-board SDE can generate full or partial integrals of the pulses, pulse-shape characterization (PSD) data, coincidence signal indication, fast timing, or other information. Likewise, external PC-based SDE post-processing software can readily be developed and applied by undergraduate students or instructors using one of several different software languages available: matlab, python, LabVIEW, root, basic, etc. As demonstrated here, an SDE-based system is a cost-effective substitute for many dedicated NIM or CAMAC electronics modules as this requires only a single digitizer module and a computer. A single digitizer with SDE is easily adapted for use in many different experiments. Applications of various high- and low-speed digitizers with SDE for many other types of physics teaching lab experiments will also be discussed.
    • Multiplicity counting using organic scintillators to distinguish neutron sources: An advanced teaching laboratory

      • Darby, Flynn B.; Hua, Michael Y.; Pakari, Oskari V.; Clarke, Shaun D.; Pozzi, Sara A., Am. J. Phys. 91, 936-945 (2023)
      • https://doi.org/10.1119/5.0139531
      • In this advanced instructional laboratory, students explore complex detection systems and nondestructive assay techniques used in the field of nuclear physics. After setting up and calibrating a neutron detection system, students carry out timing and energy deposition analyses of radiation signals. Through the timing of prompt fission neutron signals, multiplicity counting is used to carry out a special nuclear material (SNM) nondestructive assay. Our experimental setup is comprised of eight trans-stilbene organic scintillation detectors in a well-counter configuration, and measurements are taken on a spontaneous fission source as well as two (a,n) sources. By comparing each source's measured multiplicity distribution, the resulting measurements of the (a,n) sources can be distinguished from that of the spontaneous fission source. Such comparisons prevent the spoofing, i.e., intentional imitation, of a fission source by an (a,n) neutron source. This instructional laboratory is designed for nuclear engineering and physics students interested in organic scintillators, neutron sources, and nonproliferation radiation measurement techniques. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/ licenses/by/4.0/).
  • optics

    • Experiments on the Interaction of Light and Sound for the Advanced Laboratory

      • Pierce, D. T.; Byer, R. L., Am. J. Phys. 41, 314-325 (1973)
      • https://doi.org/10.1119/1.1987217
      • We describe an advanced laboratory experiment in which both Raman-Nath and Bragg diffraction of light by acoustic waves in water are observed in the sound frequency range from 5 to 45 MHz. The apparatus consists of a laser, light detector, rf power source, quartz transducer, and homemade water cell. We discuss the theory of Raman-Nath diffraction, Bragg diffraction, and the criteria for the manifestation of each. The measured Raman-Nath diffracted orders give a visual display of FM sidebands. We discuss a quantitative relationship between the incident and diffracted light and the sound for Bragg diffraction in terms of a three-wave parametric process. Stanford students in the Advanced Applied Physics Laboratory have successfully performed this experiment during the past three years.
    • An optical diffraction experiment for the advanced laboratory

      • Dodds, S. A., Am. J. Phys. 58, 663-668 (1990)
      • https://doi.org/10.1119/1.16429
      • By treating scalar diffraction as a Fourier transform problem, it is possible to calculate the expected intensity patterns for arbitrary apertures using standard signal‐processing software on a personal computer. This article presents a series of experiments on optical diffraction and spatial filtering phenomena, and quantitatively compares the results with calculations. Both the experimental and calculational methods are suitable for an advanced undergraduate laboratory.
    • Faraday rotation in the undergraduate advanced laboratory

      • Pedrotti, Frank L.; Bandettini, Peter, Am. J. Phys. 58, 542-545 (1990)
      • https://doi.org/10.1119/1.16445
      • A Faraday rotation experiment is described for laser beams of two wavelengths in moderate magnetic fields, using flint glasses of large rotary birefringence and (liquid) carbon disulfide. Results show a linear relation between angle of rotation and field strength, and indicate a strong dependence on wavelength, attributable to the dispersion, which is determined from a measurement of the Verdet constant. The theoretical treatment and experimental technique are recommended for the advanced undergraduate laboratory.
    • Laser Doppler velocimetry using a bulk optic Michelson interferometer: A student laboratory experiment

      • Belansky, Richard H.; Wanser, Keith H., Am. J. Phys. 61, 1014-1019 (1993)
      • https://doi.org/10.1119/1.17384
      • The Doppler frequency of reflected light from a moving mirror is measured using a Michelson interferometer and a low cost spectrum analyzer. The experimental data for the Doppler frequency are in agreement with the calculated theoretical values with a standard percent error of 0.54%. The concept of optical mixing of a phase‐modulated signal with the Doppler signal is presented, with a derivation of the resulting detected signal power, using the small phase modulation amplitude approximation. An experiment is described using laser Doppler velocimetry to heterodyne the Doppler signal with an acoustic wave. The experiment provides a good illustration of the Doppler effect, spectral analysis, and principles of optical mixing and interferometry in an advanced undergraduate laboratory.
    • Transmission spectroscopy of a thin membrane

      • Nachman, Paul, Am. J. Phys. 61, 564-567 (1993)
      • https://doi.org/10.1119/1.17210
      • A few‐micron‐thick nitrocellulose membrane stretched flat across an open frame (a ‘‘pellicle’’) has gently modulated passbands typically spaced by 20–60 nm across the visible and near‐infrared. This makes it an attractive subject for an upper‐division laboratory exercise. In our experiment, students determine the membrane’s thickness d and refractive index n from spectra recorded over a range of incidence angles. These spectra illustrate the classical textbook problem of transmission by a parallel plate and yield values of d and n with uncertainties less than 1%.
    • Using a moving diffraction grating to simulate the function of an acousto‐optic modulator

      • Corey, R.; Schmidt, A.; Saulnier, P., Am. J. Phys. 64, 614-617 (1996)
      • https://doi.org/10.1119/1.18164
      • We present an instructional undergraduate laboratory that introduces the student to an acousto‐optic modulator (AOM) in the context of an optical heterodyning experiment. A moving diffraction grating is used to illustrate the internal functioning of an acousto‐optic modulator and to make optical heterodyning experiments accessible to any undergraduate laboratory. The concepts and techniques presented can be used from the introductory through advanced level, in that, students gain direct laboratory experience with diffraction, the Doppler shift of light, construction of a Mach–Zehnder interferometer, optical path length measurements using a heterodyne technique, and sophisticated data analysis techniques.
    • Scanning, spherical-mirror Fabry-Perot interferometer: An upper-division optics laboratory experiment

      • Nachman, P.; Bernstein, A. C., Am. J. Phys. 65, 202-213 (1997)
      • https://doi.org/10.1119/1.18572
      • Students in our upper-division/graduate physical optics laboratory course assemble a high-finesse Fabry-Perot interferometer (FPI) from components, mode-match it to a helium-neon (HeNe) laser, and examine some of the FPI system's properties and uses. Here, we specify the necessary equipment and describe experimental procedures. For example, the experiments use the FPI's high spectral resolution to monitor the laser's behavior as it warms up; in another experimental step, they confront the issue of the photodetection system's electronic bandwidth. We also provide a review of Gaussian beam formulas and detail their use in mode-matching calculations. (C) 1997 American Association of Physics Teachers.
    • The Fréedericksz transition in liquid crystals: An undergraduate experiment for the advanced laboratory

      • Moses, Thomas; Jensen, Brian, Am. J. Phys. 66, 49-56 (1998)
      • https://doi.org/10.1119/1.18807
      • The Fréedericksz transition is a magnetically induced reorientation of the molecules of a liquid crystal. We describe here an experimental investigation of the Fréedericksz effect in liquid crystals for the advanced undergraduate laboratory. Besides introducing students to the novel and fascinating liquid-crystalline state of matter, the experiment serves as a valuable introduction to light propagation in an optically anisotropic medium and to the use of the calculus of variations in a somewhat unusual context. All components for the experiments are readily available and inexpensive.
    • Nonlinear laser spectroscopy and magneto-optics

      • Budker, Dmitry; Orlando, Donald J.; Yashchuk, Valeriy, Am. J. Phys. 67, 584-592 (1999)
      • https://doi.org/10.1119/1.19328
      • An experiment on nonlinear laser spectroscopy and magneto-optics at the Advanced Undergraduate Laboratory at Berkeley is described. The experiment consists of three parts. In the first part, students learn to operate a diode laser system and characterize its performance using a Fabry–Perot spectrum analyzer. In the second part, Doppler-broadened laser-induced fluorescence and Doppler-free saturated absorption spectra of the rubidium D2 line (780 nm) are recorded and analyzed. Finally, in the third part of the experiment, which we describe in greater detail, the near-resonant magneto-optical rotation is investigated. Nonlinear light-atom interaction leads to spectacular manifestations of the resonant Faraday effect—polarization plane rotation in a magnetic field applied along the direction of light propagation radically different from the linear case. In particular, narrow (∼30 Hz) effective line widths are observed in this experiment corresponding to a rotation enhancement by some seven orders of magnitude compared to the linear Faraday rotation.
    • A simple experiment for determining Verdet constants using alternating current magnetic fields

      • Jain, Aloke; Kumar, Jayant; Zhou, Fumin; Li, Lian; Tripathy, Sukant, Am. J. Phys. 67, 714-717 (1999)
      • https://doi.org/10.1119/1.19358
      • A simple experiment suitable for a senior undergraduate and graduate laboratory on the measurement of Faraday rotation using ac magnetic fields is described. The apparatus was used to measure the wavelength dependence of Verdet constants for several materials. A concentration-dependent study on ferric chloride water solution was also carried out to demonstrate that the diamagnetic and paramagnetic contributions to Faraday rotation have opposite signs.
    • Interference fringes from stabilized diode lasers

      • Basano, Lorenzo; Ottonello, Pasquale, Am. J. Phys. 68, 245-247 (2000)
      • https://doi.org/10.1119/1.19416
      • Interference fringes produced by a pair of intracavity stabilized diode laser beams, each impinging separately on one aperture of a double slit, are recorded on a linear charge-coupled device array. The peculiar result of the experiment is that the fringe system is found to persist for a time of the order of 1 ms and loses contrast for longer integration times. This implies that the individual linewidths of the two beams from the stabilized lasers are narrower than 1 kHz and that the average drift rates of the central peaks are far less than 0.1 MHz/s. The device was built within the advanced undergraduate electronics laboratory of the department of physics and represents a considerable improvement over previous demonstration apparatuses used to detect interference fringes from independent lasers.
    • Magnetic birefringence in a liquid crystal: An experiment for the advanced undergraduate laboratory

      • Moses, Thomas; Durall, Brian; Frankowiak, Gregory, Am. J. Phys. 68, 248-253 (2000)
      • https://doi.org/10.1119/1.19417
      • We describe an experiment involving an exciting phenomenon in liquid crystals, the magnetic field induced birefringence. We present a theoretical description accessible to junior- or senior-level physics majors, and we describe experiments for measuring the field and temperature dependence of the magnetic birefringence. The apparatus required for the experiment is inexpensive and/or easily constructed.
    • Fluctuation correlation spectroscopy for the advanced physics laboratory

      • Rieger, Robert; Röcker, Carlheinz; Nienhaus, G. Ulrich, Am. J. Phys. 73, 1129-1134 (2005)
      • https://doi.org/10.1119/1.2074047
      • A fluorescence correlation spectrometer is developed that is suitable for use in advanced laboratory courses. The instrument is simple to build and understand and can be constructed at a small fraction of the cost of a commercial or research-grade instrument. We demonstrate its surprisingly high performance with a simple biophysics application, the study of the binding of two complementary DNA strands. The instrument will be useful in areas of physics where precise measurements of the dynamics of fluorescent (or fluorescently labeled) molecules or nanoparticles in solution are of interest.
    • Two-photon spectroscopy of rubidium using a grating-feedback diode laser

      • Olson, Abraham J.; Carlson, Evan J.; Mayer, Shannon K., Am. J. Phys. 74, 218-223 (2006)
      • https://doi.org/10.1119/1.2173278
      • We describe an experiment for investigating the 5S1∕2→5D5∕2 two-photon transition in rubidium using a single grating-feedback diode laser operating at 778.1nm (385THz). Continuous tuning of the laser frequency over 4GHz allows for the clear resolution of the Doppler-free spectral features and allows accurate measurement of the hyperfine ground-state splitting. A direct comparison between Doppler-broadened and Doppler-free spectral features is possible because both are distinctly evident in the two-photon spectra. By independently modifying the polarization state of the two laser fields, the impact of electric dipole selection rules on the two-photon transition spectra is investigated. This experiment is a valuable addition to the advanced undergraduate laboratory because it uses much of the same equipment as the single-photon saturated absorption spectroscopy experiment performed on the 5S1∕2→5P3∕2 transition in rubidium (λ=780.24nm) and provides students with an opportunity to investigate characteristics of atomic spectra not evident in the single-photon experiment.
    • An electrochromic film device to teach polymer electrochemical physics

      • Huang, Mei-Rong; Tao, Tao; Li, Xin-Gui; Gong, Qian-Cheng, Am. J. Phys. 75, 839-843 (2007)
      • https://doi.org/10.1119/1.2746365
      • We discuss the background associated with an electrochromic device that can reversibly change its color and. optical density at a specific potential. We discuss the underlying science needed to make a new polyaniline (PAN)/polyvinyl alcohol(PVA) electrochromic composite film on an indium-tin oxide (ITO) conducting glass by electropolymerization and describe a reversible redox transition of the PAN. The experiment gives students an opportunity to fabricate an electrochromic device containing PAN, one of the most important conducting polymers. The experimental conditions are flexible so that each group of students can construct their own electrochromic device with particular behavior. Two techniques for polymerizing the PAN and three methods of demonstrating the electrochromism are given, depending on the available apparatus. A sophisticated three-electrode potentiostat or a crude apparatus containing a battery, wire, a variable resistor, and a voltage meter is used to synthesize the PAN deposit. The electrochromic property is repetitively observed by reversibly changing the applied potentials on the device. A potentiostatic apparatus, a single flashlight battery, or a flashlight battery accompanied by a variable resistor allows students to observe multicolor electrochromism. The experiments significantly enhance students' understanding of polymer chemicophysics principles and their appreciation of novel variable colorful films. The experiments are safe and easy to perform, provided that appropriate precautions are taken. (c) 2007 American Association of Physics Teachers.
    • A case study for optics: The solid immersion microscope

      • Vamivakas, A. Nickolas; Younger, Richard D.; Goldberg, Bennett B.; Swan, Anna K.; Ünlü, M. Selim; Behringer, Ernest R.; Ippolito, Stephen B., Am. J. Phys. 76, 758-768 (2008)
      • https://doi.org/10.1119/1.2908186
      • Microscopes are natural objects of study in introductory and upper level courses that cover optics because they are used in most science and engineering disciplines. The solid immersion microscope has been developed to study a variety of physical systems with high resolution and we suggest its inclusion in upper level optics courses. We briefly describe the solid immersion microscope in the context of geometrical optics and a desktop demonstration. We use the angular spectrum representation to calculate the focal fields produced by a conventional microscope and a solid immersion microscope. We also suggest a simple model for lens aberration and perform numerically the focal field calculations with and without aberrations to enable users to compare the performance of conventional and solid immersion microscopes. These calculations can help users develop intuition about the sensitivity of microscope performance to real-world manufacturing tolerances and to the limitations and capabilities of microscopy.
    • Generation of Bessel beams using a 4-f spatial filtering system

      • Kowalczyk, Jeremy M. D.; Smith, Stefanie N.; Szarmes, Eric B., Am. J. Phys. 77, 229-236 (2009)
      • https://doi.org/10.1119/1.3033743
      • We demonstrate a simple and straightforward method of producing Bessel beams using a 4-f spatial filtering system that requires no specialized optical components. The experiment employs the established technique of diffraction from a thin ring source, but the ring source is produced by the high-pass filtering of a uniformly illuminated circular aperture, yielding Bessel beams with a central spot radius of less than 35μm which persist over a distance of 160mm. The experiment unifies diffraction theory, Fourier optics, and the properties of Bessel beams in a manner appropriate for an advanced undergraduate laboratory.
    • Measuring the dispersion curve of a PMMA-fibre optic cable using a dye laser

      • Zorba, Serkan; Farah, Constantine; Pant, Ravi, Eur. J. Phys. 31, 1369 (2010)
      • https://dx.doi.org/10.1088/0143-0807/31/6/006
      • An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and the other coupled to the optical fibre cable at the end of which there is another photodetector. The difference in time of arrival at the detectors is used to compute the speed of light in the fibre for a given colour. In addition to a pedagogically simple and intuitive demonstration of the measurement of index of refraction, the use of a long fibre eliminates the need to direct the dangerous UV/visible laser pulse beam across a classroom, as is usually done in similar experiments. Ways to avoid systematic errors and other technical pitfalls—such as ringing oscillations—are presented.
    • Measurement of sub-natural linewidth AC Stark shifts in cold atoms: An experiment for an advanced undergraduate laboratory

      • Kleykamp, J. D.; Hachtel, A. J.; Kane, D. G.; Marshall, M. D.; Souther, N. J.; Harnish, P. K.; Bali, S., Am. J. Phys. 79, 1211-1217 (2011)
      • https://doi.org/10.1119/1.3633702
      • We measure sub-MHz AC Stark shifts, also known as light shifts, in an undergraduate laboratory setting using Raman pump-probe spectroscopy to observe sub-natural linewidth spectral features in the transmission spectrum of a weak probe beam passing through a sample of cold 85Rb atoms confined in a magneto-optical trap. To make this observation a pair of inexpensive fast photodiodes and acousto-optic modulators is needed, in addition to equipment commonly found in advanced undergraduate optics labs with laser cooling and atom trapping setups. A theoretical description of light shifts accessible to junior and senior-level physics majors is provided. (C) 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3633702]
    • Demonstration of optical spatial coherence using a variable width source

      • Sharpe, J. P.; Collins, D. A., Am. J. Phys. 79, 554-557 (2011)
      • https://doi.org/10.1119/1.3549723
      • We describe an experiment that clearly shows the change in optical spatial coherence as a function of source size. The experiment is easy to set up, requires modest equipment, and gives a striking demonstration of the celebrated phase shift of the interference fringes. The experiment yields quantitative results that agree well with theory. Setup and data acquisition are suitable for a 3 h upper division undergraduate physics laboratory.
    • Optical trap kits: issues to be aware of

      • Alexeev, I.; Quentin, U.; Leitz, K.-H.; Schmidt, M., Eur. J. Phys. 33, 427 (2012)
      • https://dx.doi.org/10.1088/0143-0807/33/2/427
      • An inexpensive and robust optical trap system can be built from off-the-shelf optical and opto-mechanical components or acquired as a kit to be assembled in a laboratory. The primary advantages of such a trap, besides being significantly more affordable, are its flexibility, and ease of modification and upgrade. In this paper, we consider several important issues to be addressed during development and application of a kit system. We numerically examine the performance of trapping systems equipped with oil and water immersion focusing objectives. We also investigate the effect of trapping laser beam quality on optical tweezing.
    • An undergraduate measurement of radiative broadening in atomic vapor

      • Hachtel, A. J.; Kleykamp, J. D.; Kane, D. G.; Marshall, M. D.; Worth, B. W.; Barkeloo, J. T.; Kangara, J. C. B.; Camenisch, J. C.; Gillette, M. C.; Bali, S., Am. J. Phys. 80, 740-743 (2012)
      • https://doi.org/10.1119/1.3694241
      • We show that one may quantitatively investigate radiative broadening of atomic transitions in the undergraduate laboratory using a traditional saturated absorption spectroscopy setup.
    • Low-cost diffuse optical tomography for the classroom

      • Minagawa, Taisuke; Zirak, Peyman; Weigel, Udo M.; Kristoffersen, Anna K.; Mateos, Nicolas; Valencia, Alejandra; Durduran, Turgut, Am. J. Phys. 80, 876-881 (2012)
      • https://doi.org/10.1119/1.4739924
      • Diffuse optical tomography (DOT) is an emerging imaging modality with potential applications in oncology, neurology, and other clinical areas. It allows the non-invasive probing of the tissue function using relatively inexpensive and safe instrumentation. An educational laboratory setup of a DOT system could be used to demonstrate how photons propagate through tissues, basics of medical tomography, and the concepts of multiple scattering and absorption. Here, we report a DOT setup that could be introduced to the advanced undergraduate or early graduate curriculum using inexpensive and readily available tools. The basis of the system is the LEGO Mindstorms NXT platform which controls the light sources, the detectors (photo-diodes), a mechanical 2D scanning platform, and the data acquisition. A basic tomographic reconstruction is implemented in standard numerical software, and 3D images are reconstructed. The concept was tested and developed in an educational environment that involved a high-school student and a group of post-doctoral fellows.
    • Reflection of a polarized light cone

      • Brody, Jed; Weiss, Daniel; Berland, Keith, Am. J. Phys. 81, 24-27 (2013)
      • https://doi.org/10.1119/1.4765079
      • We introduce a visually appealing experimental demonstration of Fresnel reflection. In this simple optical experiment, a polarized light beam travels through a high numerical-aperture microscope objective, reflects off a glass slide, and travels back through the same objective lens. The return beam is sampled with a polarizing beam splitter and produces a surprising geometric pattern on an observation screen. Understanding the origin of this pattern requires careful attention to geometry and an understanding of the Fresnel coefficients for S and P polarized light. We demonstrate that in addition to a relatively simple experimental implementation, the shape of the observed pattern can be computed both analytically and by using optical modeling software. The experience of working through complex mathematical computations and demonstrating their agreement with a surprising experimental observation makes this a highly educational experiment for undergraduate optics or advanced-lab courses. It also provides a straightforward yet non-trivial system for teaching students how to use optical modeling software.
    • Collimated blue light generation in rubidium vapor

      • Kienlen, Marcus B.; Holte, Noah T.; Dassonville, Hunter A.; Dawes, Andrew M. C.; Iversen, Kurt D.; McLaughlin, Ryan M.; Mayer, Shannon K., Am. J. Phys. 81, 442-449 (2013)
      • https://doi.org/10.1119/1.4795311
      • We describe an experiment for generating and characterizing a beam of collimated blue light (CBL) in a rubidium vapor. Two low-power, grating-feedback diode lasers, operating at 780.2 nm (5S1/2→5P3/2) and 776.0 nm (5P3/2→5D5/2), respectively, provide step-wise excitation to the 5D excited state in rubidium. Under the right experimental conditions, cascade decay through the 6P excited state will yield a collimated blue (420-nm) beam of light with high temporal and spatial coherence. We investigate the production of a blue beam under a variety of experimental conditions and characterize the spatial coherence and spectral characteristics. This experiment provides advanced undergraduate students with a unique opportunity to investigate nonlinear optical phenomena in the laboratory and uses equipment that is commonly available in laboratories equipped to investigate diode-laser-based absorption spectroscopy in rubidium.
    • Advanced optics experiments using nonuniform aperture functions

      • Wood, Lowell T., Am. J. Phys. 81, 377-380 (2013)
      • https://doi.org/10.1119/1.4789546
      • A method to create instructive, nonuniform aperture functions using spatial frequency filtering is described. The diffraction from a single slit in the Fresnel limit and the interference from a double slit in the Fraunhofer limit are spatially filtered to create electric field distributions across an aperture to produce apodization, inverse apodization or super-resolution, and apertures with phase shifts across their widths. The diffraction effects from these aperture functions are measured and calculated. The excellent agreement between the experimental results and the calculated results makes the experiment ideal for use in an advanced undergraduate or graduate optics laboratory to illustrate experimentally several effects in Fourier optics. (C) 2013 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4789546]
    • Visible optical beats at the hertz level

      • McDonald, Mickey; Ha, Jiyoun; McGuyer, Bart H.; Zelevinsky, Tanya, Am. J. Phys. 82, 1003-1005 (2014)
      • https://doi.org/10.1119/1.4890502
      • We present a lecture demonstration that produces a visible, beating interference pattern that is the optical analog of demonstrations that produce audible, beating sound-wave interference. The setup is a compact, portable Mach-Zehnder interferometer made of optical components commonly found in laser physics laboratories. This apparatus may also be built and used in advanced laboratory courses to illustrate concepts in interferometry and laser light modulation.
    • Developing a Kerr microscope for upper-division solid-state physics laboratories

      • Neff, David; Hoemke, Anatol; Attig, Adam R.; Cordova Mireles, Hector, Am. J. Phys. 82, 574-582 (2014)
      • https://doi.org/10.1119/1.4863916
      • We have constructed a low-cost Kerr microscope for use in our upper-division solid-state laboratory course by retrofitting a polarizing microscope. It was tested by imaging the magnetic domains on the surface of the polished ferromagnetic samples Nd-Fe-B and Fe-Si. The instrument serves as a learning platform for students who use it to study essential aspects of magnetic domains, as observed using the magneto-optic Kerr effect. By applying a controlled external magnetic field to a sample, magnetic domains can be observed and manipulated in real time with the aid of a digital camera. We offer technical guidance for the development of such a microscope and outline learning objectives for undergraduates in a formal lab curriculum.
    • A low-cost mirror mount control system for optics setups

      • Gopalakrishnan, Maithreyi; Gühr, Markus, Am. J. Phys. 83, 186-190 (2015)
      • https://doi.org/10.1119/1.4895343
      • We describe a flexible, simple to build, low-cost, and computer-controlled optical mirror actuator system, developed for undergraduate research laboratories. Geared motors for hobby robotics are controlled by an Arduino microcontroller in combination with an H bridge to finely position mirror mount actuators. We present a graphical user interface based on the Python script language. The price of the fully controlled actuator system is only a small fraction of the price of a commercial system. It can be quickly implemented due to the use of open-hardware electronics. We discuss the performance of the system and give an outlook for future expansions and use in advanced optical setups.
    • Advanced lab on Fresnel equations

      • Petrova-Mayor, Anna; Gimbal, Scott, Am. J. Phys. 83, 935-941 (2015)
      • https://doi.org/10.1119/1.4929969
      • This experimental and theoretical exercise is designed to promote students' understanding of polarization and thin-film coatings for the practical case of a scanning protected-metal coated mirror. We present results obtained with a laboratory scanner and a polarimeter and propose an affordable and student-friendly experimental arrangement for the undergraduate laboratory. This experiment will allow students to apply basic knowledge of the polarization of light and thin-film coatings, develop hands-on skills with the use of phase retarders, apply the Fresnel equations for metallic coating with complex index of refraction, and compute the polarization state of the reflected light. (C) 2015 American Association of Physics Teachers.
    • Optics laboratory extensions

      • Vogel, Ron, Eur. J. Phys. 36, 55045 (2015)
      • https://dx.doi.org/10.1088/0143-0807/36/5/055045
      • Most of the optics experiments done in beginning or advanced labs have ultrasonic analogs which can be used to demonstrate much of what can be done in the optics labs. These analogs can be used as a substitute for the corresponding optics experiments or in conjunction with them. And the ultrasonic experiments can be used to demonstrate several phenomena of wave propagation that are difficult to do with optics. For example, experiments can be done to observe the effects in the time domain of pulse excitation, something which is rarely done in optics, and the results used to expand student understanding of optics. The methods of several of these experiments are the subject of this paper, and comparisons will be made with what can be demonstrated with the corresponding optics experiments.
    • The Poincare-sphere approach to polarization: Formalism and new labs with Poincare beams

      • Jones, Joshua A.; D'Addario, Anthony J.; Rojec, Brett L.; Milione, G.; Galvez, Enrique J., Am. J. Phys. 84, 822-835 (2016)
      • https://doi.org/10.1119/1.4960468
      • We present a geometric-analytic introductory treatment of polarization based on the circular polarization basis, which connects directly to the Poincare sphere. This treatment enables a more intuitive way to arrive at the polarization ellipse from the components of the field. We also present an advanced optics lab that uses Poincare beams, which have a polarization that is spatially variable. The physics of this lab can reinforce understanding of all states of polarization, and in particular, elliptical polarization. In addition, it exposes students to Laguerre-Gauss modes, the spatial modes used in creating Poincare beams, which have unique physical properties. In performing this lab, students gain experience in experimental optics, such as aligning and calibrating optical components, using and programming a spatial light modulator, building an interferometer, and performing polarimetry measurements. We present the apparatus for doing the experiments, detailed alignment instructions, and lower-cost alternatives. (C) 2016 American Association of Physics Teachers.
    • Undergraduate experiments on statistical optics

      • Scholz, Ruediger; Friege, Gunnar; Weber, Kim-Alessandro, Eur. J. Phys. 37, 55302 (2016)
      • https://dx.doi.org/10.1088/0143-0807/37/5/055302
      • Since the pioneering experiments of Forrester et al (1955 Phys. Rev. 99 1691) and Hanbury Brown and Twiss (1956 Nature 177 27; Nature 178 1046), along with the introduction of the laser in the 1960s, the systematic analysis of random fluctuations of optical fields has developed to become an indispensible part of physical optics for gaining insight into features of the fields. In 1985 Joseph W Goodman prefaced his textbook on statistical optics with a strong commitment to the ‘tools of probability and statistics’ (Goodman 2000 Statistical Optics (New York: John Wiley & Sons Inc.)) in the education of advanced optics. Since then a wide range of novel undergraduate optical counting experiments and corresponding pedagogical approaches have been introduced to underpin the rapid growth of the interest in coherence and photon statistics. We propose low cost experimental steps that are a fair way off ‘real’ quantum optics, but that give deep insight into random optical fluctuation phenomena: (1) the introduction of statistical methods into undergraduate university optical lab work, and (2) the connection between the photoelectrical signal and the characteristics of the light source. We describe three experiments and theoretical approaches which may be used to pave the way for a well balanced growth of knowledge, providing students with an opportunity to enhance their abilities to adapt the ‘tools of probability and statistics’.
    • Sagnac effect in an off-center rotating ring frame of reference

      • Schwartz, Eyal, Eur. J. Phys. 38, 15301 (2016)
      • https://dx.doi.org/10.1088/0143-0807/38/1/015301
      • Interference resides deeply in our understanding of the wave properties of light. In this paper, the century famous Sagnac effect is demonstrated to be independent of the rotation axis position, using a rotating ring optical fiber in a straightforward laboratory experiment. A simple theoretical explanation for this result is given for any arbitrary closed loop interferometer. The level of this discussion should be suitable for undergraduate physics or engineering courses where electromagnetic theory and optics are discussed. The experiment described utilizes basic and important aspects in modern optics which every science student should acquire.
    • White light Sagnac interferometer—a common (path) tale of light

      • Schwartz, Eyal, Eur. J. Phys. 38, 65301 (2017)
      • https://dx.doi.org/10.1088/1361-6404/aa8192
      • White or polychromatic light sources are vastly abundant in nature and lie in our most basic understanding of the theory of light, beginning from stars like our Sun and extending to every common household light bulb or street lamp. In this paper, I present concepts of white light interferometery using a common-path Sagnac interferometer, manifested in a straightforward laboratory experiment. I further show the use of this as a Fourier transform spectrometer while presenting a basic overview of the theoretical concepts and spectrum of different light sources obtained experimentally. This work, both experimentally and analytically, is suitable for upper-level undergraduate physics or engineering courses where electromagnetic theory and optics are discussed. The experiment and theory presents important deep concepts and aspects in modern optics and physics that every science student should acquire.
    • Subtleties with Young's double-slit experiment: Investigation of spatial coherence and fringe visibility

      • Jackson, David P.; Ferris, Natalie; Strauss, Ruthie; Li, Hongyi; Pearson, Brett J., Am. J. Phys. 86, 683-689 (2018)
      • https://doi.org/10.1119/1.5047438
      • We discuss Young's double-slit experiment using a partially coherent light source consisting of a helium-neon laser incident on a rotating piece of white paper. Such an experiment is appropriate for undergraduate students as an independent project or as part of an advanced lab course. As is well known, the resulting interference pattern is observed to disappear and return, depending on the angular size of the source. Interestingly, while the standard theoretical prediction for the light intensity agrees quite well with experimental data when the fringe visibility is high, the prediction is noticeably off when the visibility is low. A first-principles calculation of the light intensity is performed and shown to agree extremely well with the experimental results for all visibilities.
    • How do phase-shifting algorithms work?

      • Juarez-Salazar, Rigoberto; Mendoza-Rodriguez, Ceciibet; Hernandez-Beltran, Jose E.; Robledo-Sanchez, Carlos, Eur. J. Phys. 39, 65302 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aae3c2
      • Interference is an important phenomenon that plays a key role in understanding the properties of light. However, novice students have difficulties with optical interference experiments because fringe-pattern processing algorithms are not a topic of optics courses. The difficulty increases taking into account that the phase shift is usually induced manually and advanced phase-shifting algorithms must be applied. In this paper, the fundamental principles behind seven well-established phase-shifting algorithms are presented. First, five basic algorithms are analyzed: the three-, four-, and n-steps as well as two least-squares algorithms. Then, the advanced iterative algorithm and the generalized phase-shifting are studied. The operation of the algorithms is illustrated by a typical experiment on the Michelson interferometer. This work could be useful as an introductory lesson to the optics laboratory.
    • Spectroscopy of neon for the advanced undergraduate laboratory

      • Busch, H. C.; Cooper, M. B.; Sukenik, C. I., Am. J. Phys. 87, 223-229 (2019)
      • https://doi.org/10.1119/10.0001318
      • We describe a spectroscopy experiment, suitable for upper-division laboratory courses, that investigates saturated absorption spectroscopy and polarization spectroscopy in a neon discharge. Both experiments use nearly identical components, allowing students to explore both techniques in a single apparatus. Furthermore, because the wavelength of the laser is in the visible part of the spectrum (640 nm), the experiment is well-suited for students with limited experience in optical alignment. The labs nicely complement a course in atomic or plasma physics, provide students with the opportunity to gain important technical skills in the area of optics and lasers, and can provide an introduction to radio-frequency electronics. (C) 2019 American Association of Physics Teachers.
    • Femtosecond laser spectroscopy, autocorrelation, and second harmonic generation: an experiment for undergraduate students

      • Sullivan, Michaela; Desmarais, Sarah; Pacheco, Everton; Hamalian, Mark; Moutsopoulos, Eirene; Patel, Hiral; Scala, Steve; Sudhu, Yasmine; Schnitzer, Cheryl, Eur. J. Phys. 40, 35302 (2019)
      • https://dx.doi.org/10.1088/1361-6404/ab07d0
      • College educators have an implicit obligation to teach students today about optics and photonics for the jobs of tomorrow. This experiment is designed for upper-level undergraduates to work in a femtosecond laser lab. The optics are aligned prior to students arriving in the lab for ease of instruction. While performing the experiment, students are allowed to move a translation stage, which functions to overshoot or delay the arrival of the translation arm laser pulse at a nonlinear beta-barium borate (BBO) crystal relative to the arrival of the stationary arm laser pulse. Ultimately, students generate an autocorrelation of the laser pulse using second harmonic generation (SHG) from the BBO crystal and the femtosecond pulse duration. Students benefit from seeing the inner-workings of a femtosecond laser and the experimental setup. Moreover, they begin to understand SHG, consider laser applications, and get a glimpse of a possible career focus.
    • LIGO analogy lab—A set of undergraduate lab experiments to demonstrate some principles of gravitational wave detection

      • Ugolini, Dennis; Rafferty, Hanna; Winter, Max; Rockstuhl, Carsten; Bergmann, Antje, Am. J. Phys. 87, 44-56 (2019)
      • https://doi.org/10.1119/1.5066567
      • The first direct detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in September 2015 proved their existence, as predicted by Einstein's General Theory of Relativity, and ushered in the era of gravitational-wave interferometry. In this article, we present a set of lab course experiments at different levels of advancement, which give students insight into the basic LIGO operating principle and advanced detection techniques. Starting with methods for folding an optical cavity, we advance to analogy experiments with sound waves that can be detected with a Michelson interferometer with an optical cavity arm. In that experiment, students also learn how the sensitivity of the device can be tuned. In a last step, we show how optical heterodyne detection (the mixing of a signal with a reference oscillator) was used in Initial LIGO. We hope these experiments not only give students an understanding of some LIGO techniques but also awaken a fascination for how unimaginably tiny signals, created by powerful cosmic events a billion years ago or earlier, can be detected today here on Earth.
    • Making an efficient but cost-effective automated goniometric device for a light-scattering study

      • Deb, Dwaipayan, Eur. J. Phys. 42, 15303 (2020)
      • https://dx.doi.org/10.1088/1361-6404/abb713
      • A goniometer is an instrument which is frequently used in optics and other branches of physics. It enables the study of light scattered in various directions from a solid, liquid or powdered sample. The goniometric instruments that are already available on the market are designed for a specific purpose and are quite costly. Fully-computerized devices—which automatically acquire data and control the positions of the light source and detector—are even more expensive. In this work, the instrumentation of a self-fabricated, low cost, but fully computerized goniometric instrument designed for studying a light-scattering problem in planetary science is described in detail. This device uses Arduino microcontroller boards for acquiring data, and stepper motors are employed for automated control of the positions of the light source and detector. A low-cost but high-intensity laser diode was used as the light source, and a very sensitive photodiode integrated circuit was used as the light detector. This work has a pedagogical value in the sense that the reader will benefit from learning about the techniques used, the components and their calibration, the software, etc. More importantly, the cost-effectiveness of this work may be beneficial to many experimentalists and instrument designers working in this field, to control their project budgets.
    • Single photon beat note in an acousto-optic modulator-based interferometer

      • Mathevet, Renaud; Chalopin, Benoit; Massenot, Sébastien, Am. J. Phys. 88, 313-318 (2020)
      • https://doi.org/10.1119/10.0000299
      • We present in the following a quantum optics experiment appropriate for advanced undergraduate students with former experience in quantum optics. It extends classical single photon setups to the time dependent domain. We demonstrate self-heterodyning of heralded single photons using a Mach-Zehnder like interferometer where beamsplitters are replaced by two acousto-optic modulators (AOMs). The single photon beat note is recorded over time at the frequency difference between the RF generators driving the AOMs, which makes it observable directly on a human time scale, i.e., with periods above a fraction of a second. To compare with our observations, we tailor the standard quantum optics formalism for beam splitters to take into account the frequency shifts associated with the AOMs.
    • An autocollimator with sub-microradian sensitivity

      • Pelle, N.; Ehinger, L.; Zaug, C. R.; Kim, W. J., Am. J. Phys. 88, 586-591 (2020)
      • https://doi.org/10.1119/10.0001269
      • We present a simple autocollimator with sub-microradian sensitivity. To demonstrate the capabilities of our autocollimator, we study the simple harmonic motion of a cantilever beam and apply an external force to affect the cantilever's resonant frequency in the context of dynamic force microscopy. Our setup is ideal for the advanced undergraduate instructional laboratory and allows a variety of high-precision, tabletop experiments.
    • An undergraduate experiment to illustrate spatial transfer function concepts in Fourier optics

      • Salvi, Jérôme; Fanjoux, Gil; Boetsch, Anne; Giust, Remo, Am. J. Phys. 88, 617-624 (2020)
      • https://doi.org/10.1119/10.0001319
      • Fourier analysis is a key tool in physics and engineering in the broadest sense and is particularly used in the field of optics to design and study the properties of advanced imaging systems. Fourier optics as a distinct topic is usually taught in final-year undergraduate or first-year postgraduate studies, and a wide range of teaching approaches have been used to describe and explain its key concepts. Concerning practical work to accompany classroom lectures, the simplest laboratory experiments are based on studying how the properties of some diffracting aperture (pupil) are related to the corresponding Fraunhofer diffraction pattern, but this approach usually does not consider in detail the concepts of the optical transfer function and spatial frequencies. We here describe a simple experimental setup that fills this particular gap and that illustrates the spatial frequency-domain response of a simple optical system using incoherent light. The Modulation Transfer Function is directly measured for several different pupil geometries and shows very good agreement with theoretical calculations. This experiment clearly demonstrates spatial transfer function concepts in Fourier optics, complementing and extending other studies of Fourier transforms in physics that may consider similar ideas in a time and frequency signal-processing context.
    • Ultrafast optics with a mode-locked erbium fiber laser in the undergraduate laboratory

      • Upcraft, Daniel; Schaffer, Andrew; Fredrick, Connor; Mohr, Daniel; Parks, Nathan; Thomas, Andrew; Sievert, Ella; Riedemann, Austin; Hoyt, Chad W.; Jones, R. Jason, Am. J. Phys. 89, 1152-1160 (2021)
      • https://doi.org/10.1119/10.0005890
      • We describe an ultrafast optics laboratory comprising a mode-locked erbium fiber laser, autocorrelation measurements, and a free-space parallel grating dispersion compensation apparatus. The gain spectrum of Er fiber provides a broad bandwidth capable of supporting sub-100 fs pulses centered near a wavelength of 1550 nm. The fiber laser design used here produces a train of pulses at a repetition rate of 55 MHz with pulse duration as short as 108 fs. The pulse duration is measured with a homebuilt autocorrelator using a simple Michelson interferometer that takes advantage of the two-photon nonlinear response of a common silicon photodiode. To compensate for temporal stretching of the short pulse due to group velocity dispersion in the fiber, an apparatus based on a pair of parallel gratings is used for pulse compression. A detailed part that lists in the supplementary material includes previously owned and common parts used by the telecommunications industry, which helps decrease costs of the laboratory. This provides a cost-effective way to introduce the principles of ultrafast optics to undergraduate laboratories.
    • Determination of density profile by using the refractive index in a linearly salt-stratified fluid: An experiment for an advanced undergraduate laboratory

      • Cruz-Gómez, R. C.; Velázquez-Muñoz, F. A.; Salcedo-Castro, J., Am. J. Phys. 90, 71-77 (2022)
      • https://doi.org/10.1119/10.0006353
      • This paper describes a low-cost laboratory experiment designed to demonstrate the applicability of the refractive index to study stratification in fluids. The laser refractography method was applied to a linearly vertical density profile of a salt (NaCl) stratified water column. Next, an image processing procedure was performed, consisting of the binarization and edge detection of the laser beam and its subsequent second-order polynomial best fit. Quantitatively, the whole-field results compared well with the respective measured density profiles. This method allows one to obtain quantitative measurements of density profiles in stratified fluids with good accuracy, making it a suitable experimental method for laboratory demonstrations on fluids.
    • Continuous gravitational waves in the lab: Recovering audio signals with a table-top optical microphone

      • Gardner, James W.; Middleton, Hannah; Liu, Changrong; Melatos, Andrew; Evans, Robin; Moran, William; Beniwal, Deeksha; Cao, Huy Tuong; Ingram, Craig; Brown, Daniel; Ng, Sebastian, Am. J. Phys. 90, 286-296 (2022)
      • https://doi.org/10.1119/10.0009409
      • Gravitational-wave observatories around the world are searching for continuous waves: persistent signals from sources, such as spinning neutron stars. These searches use sophisticated statistical techniques to look for weak signals in noisy data. In this paper, we demonstrate these techniques using a table-top model gravitational-wave detector: a Michelson interferometer where sound is used as an analog for gravitational waves. Using signal processing techniques from continuous-wave searches, we demonstrate the recovery of tones with constant and wandering frequencies. We also explore the use of the interferometer as a teaching tool for educators in physics and electrical engineering by using it as an “optical microphone” to capture music and speech. A range of filtering techniques used to recover signals from noisy data are detailed in the supplementary material of this article. Here, we present the highlights of our results using a combined notch plus Wiener filter and the statistical log minimum mean-square error (logMMSE) estimator. Using these techniques, we easily recover recordings of simple chords and drums, but complex music and speech are more challenging. This demonstration can be used by educators in undergraduate laboratories and can be adapted for communicating gravitational-wave and signal-processing topics to nonspecialist audiences.
    • Optical measurements on a budget: A 3D-printed ellipsometer

      • Mantia, Matthew; Bixby, Teresa, Am. J. Phys. 90, 445-451 (2022)
      • https://doi.org/10.1119/10.0009665
      • Ellipsometry is an optical analysis technique that is useful for characterizing the physical properties of a thin-film system. Light reflected from a sample surface undergoes a change in polarization due to phase delay and anisotropic reflection. This enables one to perform non-destructive measurements of film thickness, surface roughness, refractive index, and other optical constants. Ellipsometric techniques are particularly convenient for characterizing coatings or films in the semiconductor and optics industries. However, these techniques may be inaccessible to undergraduate students and educators due to the prohibitive cost of ellipsometers and similar instrumentation. In response to this roadblock, we describe the construction of a simple, inexpensive, manually operated, rotating analyzer ellipsometer (RAE). Required materials include a laser pointer, polarizing film, photometric detector, and a 3D-printed opto-mechanical framework, which are all readily accessible at most institutions. The instrument's performance was evaluated by comparing thickness measurements of tetraethyl orthosilicate films to those determined by a commercially available reflectometer. An average film thickness difference of 0.77% was measured using the two instruments.
    • Apparatus and method to recover the Mueller matrix in bright-field microscopy

      • Obando-Vasquez, Sofia; Doblas, Ana; Trujillo, Carlos, Am. J. Phys. 90, 702-714 (2022)
      • https://doi.org/10.1119/5.0081673
      • We present a simple experiment developed for the advanced physics instructional laboratory to calculate the Mueller matrix of a microscopic sample. The Mueller matrix is obtained from intensity-based images of the sample acquired by a polarization-sensitive microscope. The experiment requires a bright-field microscope and standard polarizing optical components such as linear polarizers and waveplates. We provide a practical procedure for implementing the apparatus, measuring the complete Mueller matrix of linear polarizers used as samples, and discuss the possibility of analyzing biological samples using our apparatus and method. Due to the simplicity of the apparatus and method, this experiment allows students to increase their knowledge about light polarization and initiate their training in optical instrumentation.
    • Erratum: “Advanced lab on Fresnel equations” [Am. J. Phys. 83, 935–941 (2015)]

      • Petrova-Mayor, Anna; Gimbal, Scott, Am. J. Phys. 90, 720 (2022)
      • https://doi.org/10.1119/5.0104434
      • The results in our original paper were obtained using the correct expression; therefore, they are not affected. E0,s≈0.5 (1+cos(2α) cos(2η). (1)Here, we report one error in our original paper.1 In Eq. (24), the cosine functions should be multiplied (instead of added) together. The correct expression is
    • Simulation led optical design assessments: Emphasizing practical and computational considerations in an upper division physics lecture course

      • Rossi, Vincent M., Am. J. Phys. 90, 279-285 (2022)
      • https://doi.org/10.1119/5.0064138
      • Employing simulation led optical design assessments (SLODAs) in an upper division optics course provides students with a deeper understanding of optical design, interactions, and devices, while reinforcing their understanding of computational methods. The upper division optics course discussed here did not have a required lab component as would be typical at many institutions. Therefore, the practical and expanded experiences students gained via SLODA in lieu of a laboratory experience were particularly crucial in developing advanced student understanding and skills in both optical design and computational applications. SLODA can also supplement a laboratory-based course with computational skill development. After introducing students to various computational methods during the early part of the course via scaffolding in-class preliminary computational activities, students were then assigned more complicated application based SLODA. This paper details each of the preliminary computational activities and SLODA, including their implementation and both the optical and computational considerations these activities and assessments were designed to introduce. An example SLODA is detailed. A reflection on the implementation of SLODA is provided for those interested in adopting the curriculum. A list of online resources is given in the Appendix for faculty wishing to implement SLODA. Finally, a sample of the student work submitted is presented and discussed in the journal's supplementary material. While success was specifically found via the implementation of SLODA in an upper division optics course, the potential exists for adaptation of the simulation led design assessment approach to other practical, design-based courses such as electronics or those within the engineering disciplines. (c) 2022 Published under an exclusive license by American Association of Physics Teachers.
    • Novel design of phase demodulation scheme for fiber optic interferometric sensors in the advanced undergraduate laboratory

      • Zhang, Gang; Ge, Qiang; Wang, Huisheng; Xuqiang, Wu; Yu, Benli, Eur. J. Phys. 43, 65301 (2022)
      • https://dx.doi.org/10.1088/1361-6404/ac93c5
      • Phase modulation depth (PMD) is crucial for the phase demodulation scheme of fiber optic interferometric sensors. The novel design of phase generated carrier differential-cross-multiplying (PGC-DCM) demodulation schemes allows undergraduates to understand the operation principle of the sensors and explore the connection between the PMD and the system performance. The system mainly consists of a laser, a fiber Michelson interferometer (FMI), a data acquisition card and a host computer. The simulation signal is first applied on the sensing arm of the FMI by a piezoelectric transducer and induces the phase difference shift between the two arms. Next the signal-to-noise ratios (SNRs) of the demodulated signals from the PGC-DCM algorithms under different PMD values are tested and an optimum PMD value is found. Thus, a proportion integral differential (PID) module is designed and integrated with the demodulation algorithm to calibrate the PMD to the optimum value. An ellipse fitting algorithm (EFA) is used to estimate the real-time PMD of the system that is then fed into the PID module. The amplitude of the laser modulation signal is controlled by the PID module, which is proportional to the PMD. Moreover, the response linearity, dynamic range, total harmonic distortion and phase resolution of the system are investigated.
    • Using lock-in detection to build a barcode scanner

      • Alexander, Riley E.; DiFrischia, Maya M.; Doubman, Margaret J.; Fabian Dubon, Stefany; Goltz, Lily; Li, Yuqian; Long, Rebecca A.; Love, Genevieve; Martinez Diers, Nina; Melpakkam, Matangi; Robinson, Catie; Tompkins, Elizabeth M.; Vanis, Avalon L. B.; Wang, Xinrui; Yu, Mallory; Spielman, Sarah E.; Noel, Michael W., Am. J. Phys. 91, 1023-1030 (2023)
      • https://doi.org/10.1119/5.0151621
      • Lock-in detection is a widely used experimental technique in which a weak signal is measured by modulating it at a particular frequency. Then, by detecting an experimental output at that frequency, the desired signal can be isolated from much larger-amplitude noise. Here, we report on the implementation and optimization of a homemade laser barcode scanner based on the lock-in technique. Our setup is comprised of components that are readily available in an undergraduate instructional laboratory. The successful transcription of the barcode into a digital signal was achieved, and this digital signal was collected with a simple computer and processed to reveal the encoded number.
    • A low-cost confocal microscope for the undergraduate lab

      • Reguilon, A.; Bethard, W.; Brekke, E., Am. J. Phys. 91, 404 (2023)
      • https://doi.org/10.1119/5.0128277
      • We demonstrate a simple and cost-efficient scanning confocal microscope setup for use in advanced instructional physics laboratories. The setup is constructed from readily available commercial products, and the implementation of a 3D-printed flexure stage allows for further cost reduction and pedagogical opportunity. Experiments exploring the thickness of a microscope slide and the surface of solid objects with height variation are presented as foundational components of undergraduate laboratory projects and demonstrate the capabilities of a confocal microscope. This system allows observation of key components of a confocal microscope, including depth perception and data acquisition via transverse scanning, making it an excellent pedagogical resource.
    • Fiber optic Michelson interference experimental course towards the cultivation of undergraduates majoring in optical engineering

      • Zhang, Min; Gao, Jiaxing; Liu, Zhihai; Zhang, Yu; Zhang, Yaxun; Yang, Xinghua; Zhang, Jianzhong; Yang, Jun; Yuan, Libo, Eur. J. Phys. 44, 45702 (2023)
      • https://dx.doi.org/10.1088/1361-6404/acd286
      • With the development of optical engineering technologies, traditional experimental courses that merely demonstrate theoretical phenomena can no longer meet the demands of optical engineers’ education. In this paper, we propose an experimental course ‘Fiber-Michelson white light interference experiment’ towards the cultivation of optical engineering undergraduates and present a fiber optic system supporting the course. The proposed course integrates fiber optics and optical engineering applications with traditional Michelson interference experimental course, and the experimental system used in the course is low in cost, easy to operate, and convenient to assemble. During the class, students work as groups and have to finish three experimental tasks including the measurements of length, curvature, and refractive index. The first-hand experiences in experiments can impress students with the Michelson optic interference theory and is conductive to developing their abilities to apply optics to engineering. Students’ feedbacks are collected by questionnaire, and students recognize the necessity and effectiveness of the course.
  • physics of lasers

    • Analysis of a four‐level laser system: Investigations of the output power characteristics of a He–Ne laser

      • Döhner, H. ‐J.; Elsässer, W., Am. J. Phys. 59, 327-330 (1991)
      • https://doi.org/10.1119/1.16542
      • The output power characteristics of a He–Ne laser are studied as an illustration of a four‐level gas laser excitation scheme. A linear dependence of the output power on the pumping rate is deduced from measurements of the output power as a function of the excitation current for various cavity lifetimes. These investigations are suitable for a laboratory course for advanced physics students.
    • A modular, reconfigurable-cavity, pulsed dye laser for the advanced undergraduate laboratory

      • Sohl, J. E.; Payton, S. G., Am. J. Phys. 65, 640-652 (1997)
      • https://doi.org/10.1119/1.18621
      • The modular pulsed dye laser described is extremely easy to build, is quickly reconfigurable into different laser cavity designs, and is usable for experiments in spectroscopy. The laser can be constructed with readily available optical components and simple hand tools. This laser is designed primarily to illustrate the performance differences of three different dye laser cavity designs: the Littrow grating (Hansch) cavity, and both the single- and double-grating grazing incidence cavities. In the double-grating configuration, the laser's linewidth of 0.007 nm is on the order of ten times narrower than many commercially available pulsed dye lasers. Thus the laser also has excellent performance as a spectroscopic tool. Construction, typical performance, and application details are described. (C) 1997 American Association of Physics Teachers.
    • Nonlinear laser spectroscopy and magneto-optics

      • Budker, Dmitry; Orlando, Donald J.; Yashchuk, Valeriy, Am. J. Phys. 67, 584-592 (1999)
      • https://doi.org/10.1119/1.19328
      • An experiment on nonlinear laser spectroscopy and magneto-optics at the Advanced Undergraduate Laboratory at Berkeley is described. The experiment consists of three parts. In the first part, students learn to operate a diode laser system and characterize its performance using a Fabry–Perot spectrum analyzer. In the second part, Doppler-broadened laser-induced fluorescence and Doppler-free saturated absorption spectra of the rubidium D2 line (780 nm) are recorded and analyzed. Finally, in the third part of the experiment, which we describe in greater detail, the near-resonant magneto-optical rotation is investigated. Nonlinear light-atom interaction leads to spectacular manifestations of the resonant Faraday effect—polarization plane rotation in a magnetic field applied along the direction of light propagation radically different from the linear case. In particular, narrow (∼30 Hz) effective line widths are observed in this experiment corresponding to a rotation enhancement by some seven orders of magnitude compared to the linear Faraday rotation.
    • Investigation of laser fundamentals using a helium-neon laser

      • Jackson, M.; Bauen, D.; Hasbun, J. E., Eur. J. Phys. 22, 211 (2001)
      • https://dx.doi.org/10.1088/0143-0807/22/3/303
      • Using an open-frame helium-neon (He-Ne) laser and optical spectrum analyser, students performed several upper-division laboratory experiments investigating important concepts regarding laser fundamentals. Such experiments include cavity stability (mirror geometry and thermal effects), longitudinal and transverse modes, free spectral range, and mode sweeping. In this paper we discuss, in an elementary way, the experimental procedures and results obtained.
    • Two-photon spectroscopy of rubidium using a grating-feedback diode laser

      • Olson, Abraham J.; Carlson, Evan J.; Mayer, Shannon K., Am. J. Phys. 74, 218-223 (2006)
      • https://doi.org/10.1119/1.2173278
      • We describe an experiment for investigating the 5S1∕2→5D5∕2 two-photon transition in rubidium using a single grating-feedback diode laser operating at 778.1nm (385THz). Continuous tuning of the laser frequency over 4GHz allows for the clear resolution of the Doppler-free spectral features and allows accurate measurement of the hyperfine ground-state splitting. A direct comparison between Doppler-broadened and Doppler-free spectral features is possible because both are distinctly evident in the two-photon spectra. By independently modifying the polarization state of the two laser fields, the impact of electric dipole selection rules on the two-photon transition spectra is investigated. This experiment is a valuable addition to the advanced undergraduate laboratory because it uses much of the same equipment as the single-photon saturated absorption spectroscopy experiment performed on the 5S1∕2→5P3∕2 transition in rubidium (λ=780.24nm) and provides students with an opportunity to investigate characteristics of atomic spectra not evident in the single-photon experiment.
    • Measuring the speed of light using beating longitudinal modes in an open-cavity HeNe laser

      • D’Orazio, Daniel J.; Pearson, Mark J.; Schultz, Justin T.; Sidor, Daniel; Best, Michael W.; Goodfellow, Kenneth M.; Scholten, Robert E.; White, James D., Am. J. Phys. 78, 524-528 (2010)
      • https://doi.org/10.1119/1.3299281
      • We describe an undergraduate laboratory that combines an accurate measurement of the speed of light, a fundamental investigation of a basic laser system, and a nontrivial use of statistical analysis. Students grapple with the existence of longitudinal modes in a laser cavity as they change the cavity length of an adjustable-cavity HeNe laser and tune the cavity to produce lasing in the TEM00 mode. For appropriate laser cavity lengths, the laser gain curve of a HeNe laser allows the simultaneous operation of multiple longitudinal modes. The difference frequency between the modes is measured using a self-heterodyne detection with a diode photodetector and a radio frequency spectrum analyzer. Asymmetric effects due to frequency pushing and frequency pulling, as well as transverse modes, are minimized by simultaneously monitoring and adjusting the mode structure as viewed with a Fabry–Pérot interferometer. The frequency spacing of longitudinal modes is proportional to the inverse of the cavity length with a proportionality constant equal to half the speed of light. By changing the length of the cavity, without changing the path length within the HeNe gas, the speed of light in air can be measured to be (2.9972±0.0002)×108 m/s, which is to high enough precision to distinguish between the speed of light in air and in vacuum.
    • \mathcal Q-switching in a neodymium laser

      • Holgado, Warein; Sola, Íñigo J.; Jarque, Enrique Conejero; Jarabo, Sebastián; Roso, Luis, Eur. J. Phys. 33, 265 (2012)
      • https://dx.doi.org/10.1088/0143-0807/33/2/265
      • We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the -switching regime is achieved. Also a nonlinear crystal can be inserted in the cavity in order to have second harmonic generation. Finally, the relation between the transverse modes and the temporal emission in the -switching regime can be observed.
    • Observation of laser feedback using a grating spectrometer

      • Brekke, Erik G.; Schulz, Matthew A., Am. J. Phys. 83, 616-620 (2015)
      • https://doi.org/10.1119/1.4913785
      • We describe an experimental setup for observing the effect of optical feedback in an extended cavity diode laser. A simple grating spectrometer is used to observe the naturally occurring wavelength spread and mode spacing for the diode. When the diode is provided with optical feedback from a grating in the Littman-Metcalf configuration, the tunability of the diode is easily observed. This setup presents an intuitive and cost-effective method for demonstrating optical feedback in an advanced undergraduate laboratory setting.
    • Femtosecond laser spectroscopy, autocorrelation, and second harmonic generation: an experiment for undergraduate students

      • Sullivan, Michaela; Desmarais, Sarah; Pacheco, Everton; Hamalian, Mark; Moutsopoulos, Eirene; Patel, Hiral; Scala, Steve; Sudhu, Yasmine; Schnitzer, Cheryl, Eur. J. Phys. 40, 35302 (2019)
      • https://dx.doi.org/10.1088/1361-6404/ab07d0
      • College educators have an implicit obligation to teach students today about optics and photonics for the jobs of tomorrow. This experiment is designed for upper-level undergraduates to work in a femtosecond laser lab. The optics are aligned prior to students arriving in the lab for ease of instruction. While performing the experiment, students are allowed to move a translation stage, which functions to overshoot or delay the arrival of the translation arm laser pulse at a nonlinear beta-barium borate (BBO) crystal relative to the arrival of the stationary arm laser pulse. Ultimately, students generate an autocorrelation of the laser pulse using second harmonic generation (SHG) from the BBO crystal and the femtosecond pulse duration. Students benefit from seeing the inner-workings of a femtosecond laser and the experimental setup. Moreover, they begin to understand SHG, consider laser applications, and get a glimpse of a possible career focus.
    • Measurement of laser beam spatial profile by laser scanning

      • Merlemis, Nikolaos; Kesidis, Anastasios L.; Sianoudis, Ioannis, Eur. J. Phys. 42, 15304 (2020)
      • https://dx.doi.org/10.1088/1361-6404/abba01
      • In several undergraduate courses related to laser physics and optics it is crucial that students should be able to understand basic concepts of laser beam propagation. In addition, experimental activities focusing on capability building in photogrammetry and remote sensing technologies are considered essential for geoinformatics undergraduate studies and for sustainable development of geospatial sciences. The understanding of laser beam scanning technologies and the fundamental physics of laser beam propagation are key factors in order to awaken students’ motivation to study remote sensing technologies. Recent advances in CCD sensors and beam profiler systems have made the measurement of laser beam spatial profile easy and accurate. However, an experiment based solely on a beam profiler could have lower pedagogical impact than expected, especially in the case of courses where scanning technology understanding is considered fundamental. With this in mind, we propose a straightforward laboratory experiment based on a modified pinhole technique where instead of using a spinning blade or a pinhole to cut the beam, a galvanometer scanner is employed to drive the laser beam through a small pinhole and record its intensity passing with a photodetector. Students are able to visualize the spatial profile of a laser beam, calculate the beam width and divergence and compare their results with direct measurement with a CCD sensor. The capability to efficiently control the scanning mechanism and take simple measurements of the spatial profile of the beam can significantly help the educational process toward the examination of more complex issues of remote sensing technologies.
    • A basic introduction to ultrastable optical cavities for laser stabilization

      • Boyd, Jamie A.; Lahaye, Thierry, Am. J. Phys. 92, 50-58 (2024)
      • https://doi.org/10.1119/5.0161369
      • We give a simple introduction to the properties and use of ultrastable optical cavities, which are increasingly common in atomic and molecular physics laboratories for stabilizing the frequency of lasers to linewidths at the kHz level or below. Although the physics of Fabry-Perot interferometers is part of standard optics curricula, the specificities of ultrastable optical cavities, such as their high finesse, fixed length, and the need to operate under vacuum, can make their use appear relatively challenging to newcomers. Our aim in this work is to bridge the gap between generic knowledge about Fabry-Perot resonators and the specialized literature about ultrastable cavities. The intended audience includes students setting up an ultrastable cavity in a research laboratory for the first time and instructors designing advanced laboratory courses on optics and laser stabilization techniques.
  • plasma physics

    • Microwave Experiments for an Advanced Laboratory

      • Elmore, W. C., Am. J. Phys. 41, 865-870 (1973)
      • https://doi.org/10.1119/1.1987405
      • Four advanced undergraduate laboratory experiments using X-band microwaves are described. The experiments include microwave measurements, electron spin resonance, the cyclotron resonance of electrons, and the electron density in a plasma. Considerable experimental detail is supplied for the latter two.
    • A low‐cost experiment in plasma physics for the advanced undergraduate lab

      • Maclatchy, C. S., Am. J. Phys. 45, 910-913 (1977)
      • https://doi.org/10.1119/1.10745
      • A quantatative experiment in plasma physics requiring only a modest investment is presented. The plasma source is a seeded propane flame. The object of the experiment is to measure the characteristics of a cylindrical Langmuir probe and the ion density in the flame plasma.
    • Understanding Langmuir probe current-voltage characteristics

      • Merlino, Robert L., Am. J. Phys. 75, 1078-1085 (2007)
      • https://doi.org/10.1119/1.2772282
      • I give several simple examples of model Langmuir probe current-voltage (I-V) characteristics that help students learn how to interpret real I-V characteristics obtained in a plasma. Students can also create their own Langmuir probe I-V characteristics using a program with the plasma density, plasma potential, electron temperature, ion temperature, and probe area as input parameters. Some examples of Langmuir probe I-V characteristics obtained in laboratory plasmas are presented and analyzed. A few comments are made advocating the inclusion of plasma experiments in the advanced undergraduate laboratory. (C) 2007 American Association of Physics Teachers.
    • The use of dc glow discharges as undergraduate educational tools

      • Wissel, Stephanie A.; Zwicker, Andrew; Ross, Jerry; Gershman, Sophia, Am. J. Phys. 81, 663-669 (2013)
      • https://doi.org/10.1119/1.4811435
      • Plasmas have a beguiling way of getting students interested in physics. We argue that plasmas can and should be incorporated into the undergraduate curriculum as both demonstrations and advanced investigations of electromagnetism and quantum effects. We describe a device, based on a direct-current (dc) glow discharge tube, which allows for a number of experiments into topics such as electrical breakdown, spectroscopy, magnetism, and electron temperature.
    • Terrella for advanced undergraduate laboratory

      • Reardon, J. C.; Almagri, A. F.; Christensen, N.; Endrizzi, D. A.; Forest, C. B.; Gallogly, S.; Lambert, A.; Malewicz, S.; Milhone, J.; Nonn, P. D.; Nornberg, M. D.; Oliva, S. P.; Purcell, C., Am. J. Phys. 88, 670-675 (2020)
      • https://doi.org/10.1119/10.0001318
      • A terrella developed for the undergraduate Advanced Laboratory course in the University of Wisconsin-Madison Physics Department is described. Our terrella consists of a permanent magnet, mounted on a pedestal in a vacuum chamber, surrounded by electrodes that may be biased in various ways. The system can confine a plasma, which may, in some ways, be considered as a toy model of the plasma confined in the Earth's magnetosphere. Our axisymmetric plasma forms in a region where the magnitude of the magnetic field B is 14 G <= B <= 550 G; for typical operation, the neutral gas pressure is p similar to 10(-4) Torr. The plasma is created by thermionic emission from a hot filament. Available diagnostics are a swept Langmuir probe, a spectroscopic fiber and visible-wavelength spectrometer, and visible imaging. In two four-hour laboratory sessions, students are guided through vacuum pumpdown, connection of electrical circuits, establishment of plasma, acquisition of data, analysis of data, and critique of data. In this paper, we present student measurements of radial profiles of electron temperature T-e and density n(e) as well as imaging of mirror trapping and del B drift and curvature drift. We conclude by outlining some opportunities for additional terrella-based student experiments. (C) 2020 American Association of Physics Teachers.
    • Plasma generation by household microwave oven for surface modification and other emerging applications

      • Barnes, Benjamin K; Ouro-Koura, Habilou; Derickson, Justin; Lebarty, Samuel; Omidokun, Jesudara; Bane, Nathan; Suleiman, Othman; Omagamre, Eguono; Fotouhi, Mahdi J.; Ogunmolasuyi, Ayobami; Dominguez, Arturo; Gonick, Larry; Das, Kausik S., Am. J. Phys. 89, 372-382 (2021)
      • https://doi.org/10.1119/10.0002706
      • A simple and inexpensive method to generate plasma using a kitchen microwave oven is described in this paper. The microwave-generated plasma is characterized by spectroscopic analysis and compared with the absorption spectra of a gas discharge tube. A Paschen-like curve is observed as the microwave plasma initiation time is plotted as a function of the pressure of the plasma chamber. We have also demonstrated that this microwave-generated air plasma can be used in a multitude of applications such as: (a) surface modification of a substrate to change its wettability; (b) surface modification to change electrical/optical properties of a substrate; and (c) enhancement of adhesive forces for improved bonding of polymeric microfluidic molds, such as bonding polydimethylsiloxane (PDMS) chips to glass covers. These simple techniques of plasma generation and subsequent surface treatment and modification applications may bring new opportunities leading to new innovations not only in advanced labs, but also in undergraduate and even high school research labs.
    • Perspective: dusty plasma experiments—a learning tool for physics graduate students

      • Choudhary, Mangilal, Eur. J. Phys. 42, 53001 (2021)
      • https://dx.doi.org/10.1088/1361-6404/abfdfb
      • Plasma is an ionized gas that responses collectively to any external (or internal) perturbation. Introducing micron-sized solid dust particles into plasma makes it more interesting. The dust particles acquire large negative charges on their surface in low-temperature laboratory plasma and exhibit collective behavior similar to the ambient plasma medium. Some remarkable features of the charged dust grain medium (dusty plasma) allow us to use it as a model system to understand a number of physics phenomena at a microscopic level. In this perspective paper, the author highlights the role of dusty plasma experiments as a learning tool for undergraduate and post-graduate physics students at higher academic institutions. Students could have great opportunities to understand basic physical phenomena as well as learn about many advanced data analysis tools and techniques by performing dusty plasma (plasma) experiments. A few simple experiments in a single dusty plasma device that connect the basic physics phenomena are discussed.
  • quantum mechanics

    • Compton Effect: an Experiment for the Advanced Laboratory

      • Bartlett, A. A.; Wilson, J. H.; Lyle, O. W., Jr.; Wells, C. V.; Kraushaar, J. J., Am. J. Phys. 32, 135-142 (1964)
      • https://doi.org/10.1119/1.1970141
      • A description is given of an advanced laboratory experiment in which the student is able to verify the Compton effect in detail. The experiment allows the student to examine the angular dependence of the energy of the Compton-scattered photon and of the Compton-scattered electron. The simultaneity of the two scattered “particles” is the key to the experimental observations. The results allow one to directly verify conservation of energy for single-photon scattering events. The agreement of experiment and theory then allow one to conclude that momentum is also conserved in these encounters.
    • Advanced laboratory NMR spectrometer with applications

      • Biscegli, Clovis; Panepucci, Horacio; Farach, Horacio A.; Poole, Charles P., Jr., Am. J. Phys. 50, 48-50 (1982)
      • https://doi.org/10.1119/1.13005
      • A description is given of an inexpensive NMR spectrometer that is suitable for use in an advanced laboratory course. The application of this spectrometer to the measurement of the oil content in corn seeds and the role of polymerization are presented.
    • Modified scattering geometry for advanced undergraduate laboratory experiment on the Compton effect

      • Cornell, David A., Am. J. Phys. 52, 282-283 (1984)
      • https://doi.org/10.1119/1.13716
      • nan
    • Analysis of a four‐level laser system: Investigations of the output power characteristics of a He–Ne laser

      • Döhner, H. ‐J.; Elsässer, W., Am. J. Phys. 59, 327-330 (1991)
      • https://doi.org/10.1119/1.16542
      • The output power characteristics of a He–Ne laser are studied as an illustration of a four‐level gas laser excitation scheme. A linear dependence of the output power on the pumping rate is deduced from measurements of the output power as a function of the excitation current for various cavity lifetimes. These investigations are suitable for a laboratory course for advanced physics students.
    • Experimental verification of the Heisenberg uncertainty principle—An advanced undergraduate laboratory

      • DeYoung, P. A.; Jolivette, P. L.; Rouze, N., Am. J. Phys. 61, 560-563 (1993)
      • https://doi.org/10.1119/1.17209
      • The Heisenberg uncertainty principle can be experimentally demonstrated by combining a Mössbauer experiment with a measurement of a nuclear lifetime. The senior undergraduate students perform a Mössbauer experiment to measure the energy width of the 14.4 keV level of 57Fe followed by measurements of coincident γ rays to determine the lifetime of the level. The experiments are designed to emphasize that the uncertainty principle is inherent in the wave function rather than resulting from the measurement process.
    • Application of high-purity germanium (HPGe) detector to advanced laboratory experiment on the Compton effect

      • Hieronymus, Seth A.; Lundquist, Loraine L.; Cornell, David A., Am. J. Phys. 66, 836 (1998)
      • https://doi.org/10.1119/1.18969
      • nan
    • Digital video microscopy in the Millikan oil-drop experiment

      • Silva, Kenneth J.; Mahendra, Jacquelyn C., Am. J. Phys. 73, 789-792 (2005)
      • https://doi.org/10.1119/1.1848112
      • We report on the ease and efficacy of using digital video microscopy techniques and computer software for analyzing data from the Millikan oil-drop experiment in an introductory physics laboratory course setting with applications for more advanced laboratories.
    • Auger electron spectroscopy for the advanced student laboratory

      • Greczyło, Tomasz; Mazur, Piotr; Dębowska, Ewa, Eur. J. Phys. 30, 311 (2009)
      • https://dx.doi.org/10.1088/0143-0807/30/2/010
      • This paper presents Auger electron spectroscopy with a retarding field analyser designed for an advanced physics experiment carried out in ‘Physics Laboratory II’ at the Institute of Experimental Physics, University of Wroclaw, Poland. The authors discuss the process of setting up the experiment and the results of the measurement of Auger spectra. The advantages and disadvantages of the apparatus are discussed along with its implementation in the teaching process.
    • Photon charge experiment

      • Hankins, A.; Rackson, C.; Kim, W. J., Am. J. Phys. 81, 436-441 (2013)
      • https://doi.org/10.1119/1.4793593
      • The deflection of a laser beam traveling through a modulated electric field is measured using phase-sensitive detection to place an upper bound on the photon charge. An upper limit of 10−14e is obtained. Our approach provides a simple experimental scheme for angle measurements and is suitable as a laboratory exercise for both advanced undergraduate and beginning graduate students in physical science.
    • Inexpensive electronics and software for photon statistics and correlation spectroscopy

      • Gamari, Benjamin D.; Zhang, Dianwen; Buckman, Richard E.; Milas, Peker; Denker, John S.; Chen, Hui; Li, Hongmin; Goldner, Lori S., Am. J. Phys. 82, 712-722 (2014)
      • https://doi.org/10.1119/1.4869188
      • Single-molecule-sensitive microscopy and spectroscopy are transforming biophysics and materials science laboratories. Techniques such as fluorescence correlation spectroscopy (FCS) and single-molecule sensitive fluorescence resonance energy transfer (FRET) are now commonly available in research laboratories but are as yet infrequently available in teaching laboratories. We describe inexpensive electronics and open-source software that bridges this gap, making state-of-the-art research capabilities accessible to undergraduates interested in biophysics. We include a discussion of the intensity correlation function relevant to FCS and how it can be determined from photon arrival times. We demonstrate the system with a measurement of the hydrodynamic radius of a protein using FCS that is suitable for the undergraduate teaching laboratory. The FPGA-based electronics, which are easy to construct, are suitable for more advanced measurements as well, and several applications are described. As implemented, the system has 8 ns timing resolution, can control up to four laser sources, and can collect information from as many as four photon-counting detectors.
    • Studying the effect of polarisation in Compton scattering in the undergraduate laboratory

      • Knights, P.; Ryburn, F.; Tungate, G.; Nikolopoulos, K., Eur. J. Phys. 39, 25203 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aa9c98
      • An experiment for the advanced undergraduate laboratory allowing students to directly observe the effect of photon polarisation on Compton scattering is described. An initially unpolarised beam of photons is polarised via Compton scattering and analysed through a subsequent scattering. The experiment is designed to use equipment typically available at an undergraduate physics laboratory. The experimental results are compared with a Geant4 simulation and geometry effects are discussed.
    • Little bits of diamond: Optically detected magnetic resonance of nitrogen-vacancy centers

      • Zhang, Haimei; Belvin, Carina; Li, Wanyi; Wang, Jennifer; Wainwright, Julia; Berg, Robbie; Bridger, Joshua, Am. J. Phys. 86, 225-236 (2018)
      • https://doi.org/10.1119/1.5023389
      • We give instructions for the construction and operation of a simple apparatus for performing optically detected magnetic resonance measurements on diamond samples containing high concentrations of nitrogen-vacancy (NV) centers. Each NV center has a spin degree of freedom that can be manipulated and monitored by a combination of visible and microwave radiation. We observe Zeeman shifts in the presence of small external magnetic fields and describe a simple method to optically measure magnetic field strengths with a spatial resolution of several microns. The activities described are suitable for use in an advanced undergraduate lab course, powerfully connecting core quantum concepts to cutting edge applications. An even simpler setup, appropriate for use in more introductory settings, is also presented.
    • A z-axis tunneling microscope for undergraduate labs

      • Lindgren, Randy; Kozan, Wesley; Fuerst, Noah; Knapp, Douglas; Veazey, Joshua P., Am. J. Phys. 90, 795-800 (2022)
      • https://doi.org/10.1119/5.0094028
      • We present the design and construction of a laboratory apparatus that provides advanced undergraduates with hands-on observations of electron quantum tunneling and the electronic density of states of various materials. The instrument is inspired by the scanning tunneling microscope (STM), but its implementation is simplified by limiting the tip motion to the single dimension along the tip-sample separation (z-axis); we refer to the device as the z-axis tunneling microscope (ZTM). Students are able to use the ZTM to measure electron tunneling probability as a function of barrier width, estimate relative material work functions, and observe differences in local electronic structure among metals, semimetals, and semiconductors. We share results obtained by third-year undergraduate physics students using the instrument for their final projects in an advanced instructional lab course.
    • Observing hyperfine interactions of NV− centers in diamond in an advanced quantum teaching lab

      • Yang, Yang; Vallabhapurapu, Hyma H.; Sewani, Vikas K.; Isarov, Maya; Firgau, Hannes R.; Adambukulam, Chris; Johnson, Brett C.; Pla, Jarryd J.; Laucht, Arne, Am. J. Phys. 90, 550-560 (2022)
      • https://doi.org/10.1119/5.0075519
      • The negatively charged nitrogen-vacancy (NV−) center in diamond is a model quantum system for university teaching labs due to its room-temperature compatibility and cost-effective operation. Based on the low-cost experimental setup that we have developed and described for the coherent control of the electronic spin [Sewani et al., Am. J. Phys. 88, 1156–1169 (2020)], we introduce and explain here a number of more advanced experiments that probe the electron–nuclear interaction between the NV− electronic and the 14N and 13C nuclear spins. Optically detected magnetic resonance, Rabi oscillations, Ramsey fringe experiments, and Hahn echo sequences are implemented to demonstrate how the nuclear spins interact with the electron spins. Most experiments only require 15 min of measurement time and, therefore, can be completed within one teaching lab.
    • Testing a Bell Inequality with a Remote Quantum Processor

      • Brody, Jed; Avram, Robert, The Physics Teacher 61, 218-221 (2023)
      • https://doi.org/10.1119/5.0069073
      • IBM Quantum offers free remote access to real quantum processors. One of the many experiments now accessible to all students is a test of Bell inequalities. This experiment introduces the rigorous mysteries that physicists have grappled with for a century. Using IBM Quantum to test Bell inequalities is not new. However, we are unaware of any single reference, appropriate for introductory students, that contains (1) the derivation of a Bell inequality, (2) the derivation of the corresponding quantum prediction, and (3) instructions for carrying out the experiment with IBM Quantum.
    • Heisenberg uncertainty principle: an advanced undergraduate laboratory experiment based on quantum quadrature operators

      • Chen, Yu; Liu, Zhaoyang; Chen, Xin; Liu, Shuqi; Jiang, Jiatong; Wu, Yuan; Guo, Jinxian; Chen, L. Q., Eur. J. Phys. 44, 25302 (2023)
      • https://dx.doi.org/10.1088/1361-6404/acb4c6
      • The Heisenberg uncertainty principle (HUP) plays an important role in quantum mechanics. It is necessary to demonstrate this principle experimentally for undergraduates to understand HUP clearly. In this paper, we originally employ the quantum quadrature operators to demonstrate HUP in undergraduate laboratories. Starting from the quantization of electromagnetic field, we briefly review the definition of quadrature operators and demonstrate HUP via the variances of quadrature operators. And the scheme of HUP demonstration with homodyne detection is introduced. More importantly, we develop a tabletop experimental apparatus for the demonstration of HUP in undergraduate laboratories. Our proposal focuses on the basic quantum mechanics concepts, experimental principles, and instruction as well as experimental techniques. It provides a way to help undergraduates, especially the ones who will go on graduate study in quantum technology in the future, make connections between abstract quantum mechanics concepts and concrete experiments, which makes the concepts better understood.
    • Unexpected optimal measurement protocols in Bell's inequality violation experiments

      • Negre, Alicia; Mathevet, Renaud; Chalopin, Benoit; Massenot, Sébastien, Am. J. Phys. 91, 64-73 (2023)
      • https://doi.org/10.1119/5.0102516
      • Bell's inequality violation experiments are becoming increasingly popular in the practical teaching of undergraduate and master's degree students. Bell's parameter S is obtained from 16 polarization correlation measurements performed on entangled photons pairs. We first report here a detailed analysis of the uncertainty u(S) of Bell's parameter taking into account coincidence count statistics and errors in polarizers' orientation. We show using both computational modeling and experimental measurement that the actual sequence of the polarizer settings has an unexpected and strong influence on the error budget. This result may also be relevant to measurements in other settings in which errors in parameters may have non-random effects in the measurement.
  • relativity

    • Study of the effect of relativistic time dilation on cosmic ray muon flux—An undergraduate modern physics experiment

      • Easwar, Nalini; MacIntire, Douglas A., Am. J. Phys. 59, 589-592 (1991)
      • https://doi.org/10.1119/1.16841
      • An experiment to study the effect of relativistic time dilation on secondary muon fluxes observed at different altitudes is described in this article. Muons, produced as secondary particles from the interaction of primary cosmic rays with the upper atmosphere, form a natural and abundant source of subatomic ‘‘clocks’’ moving at very high speeds. The measured muon flux on a mountain relative to that measured at sea level can be compared to predictions from calculations that take into account the relativistic time dilation in the muon frame. Situations under which such an experiment can be successfully performed are explored with a day‐long field trip to a nearby mountain. This experiment has been developed at Smith College as a module in the Five College cooperative undergraduate advanced laboratory course (other participating institutions are Amherst College, Mount Holyoke College, and the University of Massachusetts).
    • A compact apparatus for muon lifetime measurement and time dilation demonstration in the undergraduate laboratory

      • Coan, Thomas; Liu, Tiankuan; Ye, Jingbo, Am. J. Phys. 74, 161-164 (2006)
      • https://doi.org/10.1119/1.2135319
      • We describe a compact apparatus for measuring the charge-averaged lifetime of atmospheric muons in plastic scintillator using low-cost, low-power electronics. We present measurements of the stopping rate of atmospheric muons as a function of altitude to demonstrate relativistic time dilation. The apparatus is designed for the advanced undergraduate physics laboratory and is suitable for field measurements.
    • Test of the second postulate of special relativity using positron annihilation

      • Dryzek, Jerzy; Singleton, Douglas, Am. J. Phys. 75, 713-717 (2007)
      • https://doi.org/10.1119/1.2733692
      • An experiment to directly test the second postulate of special relativity is described. The speed of photons, resulting from the annihilation of either thermal positrons or in-flight positrons (moving with relativistic velocity), is measured using two complementary variations of the same basic experiment. For both at rest and moving positrons the constancy of the speed of light was confirmed to an accuracy of approximately 1%. This apparatus can be used in an advanced undergraduate laboratory and also used to place limits on alternative theories to special relativity that have transformations other than the Lorentz transformation.
  • simulation

    • Nonlinear coupled oscillators and Fourier transforms: An advanced undergraduate laboratory

      • DeYoung, P. A.; LaPointe, D.; Levy, J.; Lorenz, W., Am. J. Phys. 64, 898-902 (1996)
      • https://doi.org/10.1119/1.18118
      • As part of an upper‐level laboratory course, the oscillations of one and two mass systems on an airtrack were measured in real time. Both linear oscillations with spring forces and nonlinear oscillations with magnetic forces were analyzed with fast Fourier transforms and compared to theoretical predictions. The results for the coupled linear oscillator agree with the theoretical values to within 0.5%. The coupled nonlinear oscillator results were modeled numerically.
    • Modeling excitable systems: Reentrant tachycardia

      • Lancaster, Jarrett L.; Hellen, Edward H.; Leise, Esther M., Am. J. Phys. 78, 56-63 (2010)
      • https://doi.org/10.1119/1.3246868
      • Excitable membranes are an important type of nonlinear dynamical system, and their study can be used to provide a connection between physical and biological circuits. We discuss two models of excitable membranes important in cardiac and neural tissues. One model is based on the Fitzhugh–Nagumo equations, and the other is based on a three-transistor excitable circuit. We construct a circuit that simulates reentrant tachycardia and its treatment by surgical ablation. This project is appropriate for advanced undergraduates as a laboratory capstone project or as a senior thesis or honors project and can also be a collaborative project, with one student responsible for the computational predictions and another for the circuit construction and measurements.
    • Reflection of a polarized light cone

      • Brody, Jed; Weiss, Daniel; Berland, Keith, Am. J. Phys. 81, 24-27 (2013)
      • https://doi.org/10.1119/1.4765079
      • We introduce a visually appealing experimental demonstration of Fresnel reflection. In this simple optical experiment, a polarized light beam travels through a high numerical-aperture microscope objective, reflects off a glass slide, and travels back through the same objective lens. The return beam is sampled with a polarizing beam splitter and produces a surprising geometric pattern on an observation screen. Understanding the origin of this pattern requires careful attention to geometry and an understanding of the Fresnel coefficients for S and P polarized light. We demonstrate that in addition to a relatively simple experimental implementation, the shape of the observed pattern can be computed both analytically and by using optical modeling software. The experience of working through complex mathematical computations and demonstrating their agreement with a surprising experimental observation makes this a highly educational experiment for undergraduate optics or advanced-lab courses. It also provides a straightforward yet non-trivial system for teaching students how to use optical modeling software.
    • Studying the effect of polarisation in Compton scattering in the undergraduate laboratory

      • Knights, P.; Ryburn, F.; Tungate, G.; Nikolopoulos, K., Eur. J. Phys. 39, 25203 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aa9c98
      • An experiment for the advanced undergraduate laboratory allowing students to directly observe the effect of photon polarisation on Compton scattering is described. An initially unpolarised beam of photons is polarised via Compton scattering and analysed through a subsequent scattering. The experiment is designed to use equipment typically available at an undergraduate physics laboratory. The experimental results are compared with a Geant4 simulation and geometry effects are discussed.
    • Simulation led optical design assessments: Emphasizing practical and computational considerations in an upper division physics lecture course

      • Rossi, Vincent M., Am. J. Phys. 90, 279-285 (2022)
      • https://doi.org/10.1119/5.0064138
      • Employing simulation led optical design assessments (SLODAs) in an upper division optics course provides students with a deeper understanding of optical design, interactions, and devices, while reinforcing their understanding of computational methods. The upper division optics course discussed here did not have a required lab component as would be typical at many institutions. Therefore, the practical and expanded experiences students gained via SLODA in lieu of a laboratory experience were particularly crucial in developing advanced student understanding and skills in both optical design and computational applications. SLODA can also supplement a laboratory-based course with computational skill development. After introducing students to various computational methods during the early part of the course via scaffolding in-class preliminary computational activities, students were then assigned more complicated application based SLODA. This paper details each of the preliminary computational activities and SLODA, including their implementation and both the optical and computational considerations these activities and assessments were designed to introduce. An example SLODA is detailed. A reflection on the implementation of SLODA is provided for those interested in adopting the curriculum. A list of online resources is given in the Appendix for faculty wishing to implement SLODA. Finally, a sample of the student work submitted is presented and discussed in the journal's supplementary material. While success was specifically found via the implementation of SLODA in an upper division optics course, the potential exists for adaptation of the simulation led design assessment approach to other practical, design-based courses such as electronics or those within the engineering disciplines. (c) 2022 Published under an exclusive license by American Association of Physics Teachers.
  • single photons / quantum optics

    • Entangled photon apparatus for the undergraduate laboratory

      • Dehlinger, Dietrich; Mitchell, M. W., Am. J. Phys. 70, 898-902 (2002)
      • https://doi.org/10.1119/1.1498859
      • We present detailed instructions for constructing and operating an apparatus to produce and detect polarization-entangled photons. The source operates by type I spontaneous parametric downconversion in a two-crystal geometry. Photons are detected in coincidence by single-photon counting modules and show strong angular and polarization correlations. We observe more than 100 entangled photon pairs per second. A test of a Bell inequality can be performed in an afternoon.
    • Entangled photons, nonlocality, and Bell inequalities in the undergraduate laboratory

      • Dehlinger, Dietrich; Mitchell, M. W., Am. J. Phys. 70, 903-910 (2002)
      • https://doi.org/10.1119/1.1498860
      • We use polarization-entangled photon pairs to demonstrate quantum nonlocality in an experiment suitable for advanced undergraduates. The photons are produced by spontaneous parametric downconversion using a violet diode laser and two nonlinear crystals. The polarization state of the photons is tunable. Using an entangled state analogous to that described in the Einstein–Podolsky–Rosen paradox, we demonstrate strong polarization correlations of the entangled photons. Bell’s idea of a hidden variable theory is presented by way of an example and compared to the quantum prediction. A test of the Clauser, Horne, Shimony, and Holt version of the Bell inequality finds S=2.307±0.035, in clear contradiction of hidden variable theories. The experiments described can be performed in an afternoon.
    • Observing the quantum behavior of light in an undergraduate laboratory

      • Thorn, J. J.; Neel, M. S.; Donato, V. W.; Bergreen, G. S.; Davies, R. E.; Beck, M., Am. J. Phys. 72, 1210-1219 (2004)
      • https://doi.org/10.1119/1.1737397
      • While the classical, wavelike behavior of light (interference and diffraction) has been easily observed in undergraduate laboratories for many years, explicit observation of the quantum nature of light (i.e., photons) is much more difficult. For example, while well-known phenomena such as the photoelectric effect and Compton scattering strongly suggest the existence of photons, they are not definitive proof of their existence. Here we present an experiment, suitable for an undergraduate laboratory, that unequivocally demonstrates the quantum nature of light. Spontaneously downconverted light is incident on a beamsplitter and the outputs are monitored with single-photon counting detectors. We observe a near absence of coincidence counts between the two detectors—a result inconsistent with a classical wave model of light, but consistent with a quantum description in which individual photons are incident on the beamsplitter. More explicitly, we measured the degree of second-order coherence between the outputs to be g(2)(0)=0.0177±0.0026, which violates the classical inequality g(2)(0)⩾1 by 377 standard deviations.
    • Interference with correlated photons: Five quantum mechanics experiments for undergraduates

      • Galvez, E. J.; Holbrow, Charles H.; Pysher, M. J.; Martin, J. W.; Courtemanche, N.; Heilig, L.; Spencer, J., Am. J. Phys. 73, 127-140 (2005)
      • https://doi.org/10.1119/1.1796811
      • We describe five quantum mechanics experiments that have been designed for an undergraduate setting. The experiments use correlated photons produced by parametric down conversion to generate interference patterns in interferometers. The photons are counted individually. The experimental results illustrate the consequences of multiple paths, indistinguishability, and entanglement. We analyze the results quantitatively using plane-wave probability amplitudes combined according to Feynman’s rules, the state-vector formalism, and amplitude packets. The apparatus fits on a 2′×4′ optical breadboard.
    • Quantum mysteries tested: An experiment implementing Hardy’s test of local realism

      • Carlson, J. A.; Olmstead, M. D.; Beck, M., Am. J. Phys. 74, 180-186 (2006)
      • https://doi.org/10.1119/1.2167764
      • We have performed a test of local realism using entangled photons produced by spontaneous parametric downconversion. This experimental test is based on an idea originally proposed by Hardy for a test of local realism without inequalities, although our experiment actually measures an inequality (as any experiment must). We find a more-than-70 standard deviation violation of the predictions of local realism. The experimental effort required for this test is essentially the same as that required for a test of a Bell inequality. However, this test is based on concepts that are easier to understand and more compelling than those behind the original Bell inequality.
    • Low-cost coincidence-counting electronics for undergraduate quantum optics

      • Branning, D.; Bhandari, S.; Beck, M., Am. J. Phys. 77, 667-670 (2009)
      • https://doi.org/10.1119/1.3116803
      • Coincidence counting is a necessary ingredient for quantum optics experiments at the undergraduate level, but cost has created an entry barrier for many schools. We present a design of a coincidence-counting module that replaces the traditional method based on time-to-amplitude conversion and pulse-height analysis. Our module accepts inputs from up to four detectors, has a coincidence-time window of less than 10ns, and has a throughput of more than triple that of the traditional method. The cost of our coincidence-counting module is less than 5% of the cost of the traditional method.
    • Qubit quantum mechanics with correlated-photon experiments

      • Galvez, Enrique J., Am. J. Phys. 78, 510-519 (2010)
      • https://doi.org/10.1119/1.3337692
      • A matrix-based formalism is used to explain the results of undergraduate level quantum mechanics experiments with correlated photons. The article includes new variations of experiments and new results. A discussion of our experience with a correlated-photon laboratory component for an undergraduate course on quantum mechanics is presented.
    • A hands-on introduction to single photons and quantum mechanics for undergraduates

      • Pearson, Brett J.; Jackson, David P., Am. J. Phys. 78, 471-484 (2010)
      • https://doi.org/10.1119/1.3354986
      • We describe a series of experiments used in a sophomore-level quantum physics course that are designed to provide students with a hands-on introduction to quantum mechanics. By measuring correlations, we demonstrate that a helium-neon laser produces results consistent with a classical model of light. We then demonstrate that a light source derived from a spontaneous parametric down-conversion process produces results that can only be described using a quantum theory of light, thus providing a (nearly) single-photon source. These single photons are then sent into a Mach–Zehnder interferometer, and interference fringes are observed whenever the path of the photons cannot be determined. These experiments are investigated theoretically using straightforward quantum-mechanical calculations.
    • The Hong–Ou–Mandel interferometer in the undergraduate laboratory

      • Carvioto-Lagos, Jorge; P, Gustavo Armendariz; Velázquez, Víctor; López-Moreno, Enrique; Grether, M.; Galvez, E. J., Eur. J. Phys. 33, 1843 (2012)
      • https://dx.doi.org/10.1088/0143-0807/33/6/1843
      • The Hong–Ou–Mandel interferometer is an optical device that allows us to prove the quantum nature of light experimentally via the quantum amplitude superposition of two indistinguishable photons. We have implemented this experiment as an advanced undergraduate laboratory experience. We were able to overcome well-known difficulties using techniques reported recently by Thomas et al (2009 Rev. Sci. Instrum. 80 036101).
    • Energy and momentum entanglement in parametric downconversion

      • Saldanha, Pablo L.; Monken, C. H., Am. J. Phys. 81, 28-32 (2013)
      • https://doi.org/10.1119/1.4757623
      • We present a simple treatment of the phenomenon of spontaneous parametric downconversion consisting of the coherent scattering of a single pump photon into an entangled photon pair inside a nonlinear crystal. The energy and momentum entanglement of the quantum state of the generated twin photons are seen as a consequence of the fundamental indistinguishability of the time and the position in which the photon pair is created inside the crystal. We also discuss some consequences of photon entanglement.
    • Teaching quantum mechanics with the Hong-Ou-Mandel interferometer

      • Armendáriz, Gustavo; Cravioto-Lagos, Jorge; Velázquez, Victor; Grether, Marcela; López-Moreno, Enrique; Galvez, E. J., 12th Education and Training in Optics and Photonics Conference 9289, 46-52 (2014)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9289/928908/Teaching-quantum-mechanics-with-the-Hong-Ou-Mandel-interferometer/10.1117/12.2070280.full
      • The Hong-Ou-Mandel interferometer is an optical device which allows us to prove experimentally the quantum nature of light via the quantum amplitude superposition of two indistinguishable photons. We have implemented this experiment as an advanced undergraduate laboratory experience. We were able to overcome well known difficulties with this experiment using recently reported techniques by Thomas et al. [Rev. Sci. Instr. 80, 036101 (2009), ].
    • Quantum optics laboratories for undergraduates

      • Beck, Mark; Dederick, Ethan, 12th Education and Training in Optics and Photonics Conference 9289, 359-366 (2014)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9289/92891G/Quantum-optics-laboratories-for-undergraduates/10.1117/12.2070525.full
      • We have developed a series of undergraduate teaching laboratories that explore some of the fundamentals of quantum mechanics. All of the experiments involve performing measurements on individual photons or entangled-photon pairs. The experiments include: "Proving" that light consists of photons, single-photon interference, and tests of local realism. We will describe the experiments, placing an emphasis on an experiment which measures the quantum-mechanical polarization state of a photon. This experiment explicitly demonstrates that measurements performed on one member of an entangled-photon pair effect the results of measurements of the other photon. We will also describe how we have integrated the experiments with our upper-level undergraduate quantum mechanics course.
    • Single-photon interference experiment for high schools

      • Bondani, Maria, 12th Education and Training in Optics and Photonics Conference 9289, 106-111 (2014)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9289/92890H/Single-photon-interference-experiment-for-high-schools/10.1117/12.2070772.full
      • We follow the reductio ad absurdum reasoning described in the book “Sneaking a Look at God’s Cards” by Giancarlo Ghirardi to demonstrate the wave-particle duality of light in a Mach-Zehnder interferometric setup analog to the conventional Young double-slit experiment. We aim at showing the double nature of light by measuring the existence of interference fringes down to the single-photon level. The setup includes a strongly attenuated laser, polarizing beam splitters, half-waveplates, polarizers and single-photon detectors.
    • Exploring entanglement with the help of quantum state measurement

      • Dederick, E.; Beck, M., Am. J. Phys. 82, 962-971 (2014)
      • https://doi.org/10.1119/1.4883230
      • We have performed a series of experiments using a spontaneous parametric down-conversion source to produce pairs of photons in either entangled or non-entangled polarization states. We determine the full quantum mechanical polarization state of one photon, conditioned on the results of measurements performed on the other photon. For non-entangled states, we find that the measured state of one photon is independent of measurements performed on the other. However, for entangled states, the measured state does depend on the results of measurements performed on the other photon. This is possible because of the nonlocal nature of entangled states. These experiments are suitable for an undergraduate teaching laboratory.
    • Resource Letter SPE-1: Single-Photon Experiments in the Undergraduate Laboratory

      • Galvez, Enrique J., Am. J. Phys. 82, 1018-1028 (2014)
      • https://doi.org/10.1119/1.4872135
      • This Resource Letter lists undergraduate-laboratory adaptations of landmark optical experiments on the fundamentals of quantum physics. Journal articles and websites give technical details of the adaptations, which offer students unique hands-on access to testing fundamental concepts and predictions of quantum mechanics. A selection of the original research articles that led to the implementations is included. These developments have motivated a rethinking of the way quantum mechanics is taught, so this Resource Letter also lists textbooks that provide these new approaches.
    • Contrasting classical probability concepts with quantum mechanical behavior in the undergraduate laboratory

      • Guzmán, D. A.; Uribe, L. J.; Valencia, A.; Rodríguez, F. J.; Quiroga, L., Eur. J. Phys. 36, 55039 (2015)
      • https://dx.doi.org/10.1088/0143-0807/36/5/055039
      • In this paper, we report an experimental activity suitable for undergraduate students that makes them question their ideas about locality and realism. The experiment here reported complements previous educational approaches to Bell inequalities, since the usually called S function, that quantifies correlations, is mapped by measuring it for different detection angles. The students themselves worked in a pre-aligned setup that allowed them to test and violate the Clauser–Horne–Shimony–Holt–Bell inequality for two distant photons entangled in polarization.
    • Mapping and violating Bell inequality with entangled photons

      • Guzmán, David A.; Uribe, Leonardo J.; Valencia, Alejandra; Rodríguez, Ferney J.; Quiroga, Luis, Education and Training in Optics and Photonics: ETOP 2015 9793, 363-366 (2015)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9793/979324/Mapping-and-violating-Bell-inequality-with-entangled-photons/10.1117/12.2223197.full
      • In 1964, J. Bell introduced an inequality that stated a mathematical bound for any physical system that holds both locality and realism; if we violate this inequality, it is clear that we have to reconsider the previous statement. In our work, we report an experimental activity with photons suitable for undergraduate students that makes them question these naïve ideas of nature’s behavior. With a pre-aligned setup, our students tested and violated Bell’s inequality in a two-hour laboratory session, using two distant photons entangled in polarization. In addition, complementing an educational approach to this phenomenon, the usually called S function, that quantifies correlations, was mapped using different detection angles in one of the two locations. In particular, a more complete picture of the S function, allow us to identify the initial state of light. We show in this work that it is possible for undergraduate students to question some of our common sense ideas of nature using experiments with photons.
    • Delayed-choice quantum eraser for the undergraduate laboratory

      • Ashby, James M.; Schwarz, Peter D.; Schlosshauer, Maximilian, Am. J. Phys. 84, 95-105 (2016)
      • https://doi.org/10.1119/1.4938151
      • In a delayed-choice quantum eraser, interference fringes are obtained by erasing which-way information after the interfering particle has already been irreversibly detected. Following an introductory review of delayed-choice experiments and quantum erasure, we describe the experimental realization of an optical delayed-choice quantum eraser, suitable for advanced undergraduates, based on polarization-entangled pairs of single photons. In our experiment, the delay of the erasure is implemented using two different setups. The first setup employs an arrangement of mirrors to increase the optical path length of the photons carrying which-way information. In the second setup, we use fiber-optic cables to elongate the path of these photons after their passage through the polarization analyzer but prior to their arrival at the detector. We compare our results to data obtained in the absence of a delay and find excellent agreement. This shows that the timing of the erasure is irrelevant, as also predicted by quantum mechanics. The experiment can serve as a valuable pedagogical tool for conveying the fundamentals of quantum mechanics.
    • Video recording true single-photon double-slit interference

      • Aspden, Reuben S.; Padgett, Miles J.; Spalding, Gabriel C., Am. J. Phys. 84, 671-677 (2016)
      • https://doi.org/10.1119/1.4955173
      • Commercially available cameras do not have a low-enough dark noise to directly capture double-slit interference at the single photon level. In this work, camera noise levels are significantly reduced by activating the camera only when the presence of a photon has been detected by the independent detection of a time-correlated photon produced via parametric down-conversion. This triggering scheme provides the improvement required for direct video imaging of Young's double-slit experiment with single photons, allowing clarified versions of this foundational demonstration. We present video data of the evolving interference patterns. Also, we introduce variations on this experiment aimed at promoting discussion of the role spatial coherence plays in such a measurement, emphasizing complementary aspects of single-photon measurement and highlighting the roles of transverse position and momentum correlations between down-converted photons, including examples of “ghost” imaging and diffraction.
    • Witnessing entanglement in an undergraduate laboratory

      • Beck, Marisol N.; Beck, M., Am. J. Phys. 84, 87-94 (2016)
      • https://doi.org/10.1119/1.4936623
      • An entangled state of a two-particle system is a quantum state that cannot be separated, meaning it cannot be written as the product of states of the individual particles. One way to tell if a system is entangled is to use it to violate a Bell inequality (such as the Clauser-Horne-Shimony-Holt, CHSH, inequality), because entanglement is necessary for such a violation. However, there are other, easier-to-perform measurements that determine whether or not a system is entangled. An operator that corresponds to such a measurement is referred to as an entanglement witness. Here, we present the theory of witness operators and an undergraduate experiment that measures entanglement witnesses for the joint polarization state of two photons. We are able to produce states for which the expectation value of a witness operator is entangled by more than 300 standard deviations. In order to further examine the performance of these witness operators, we present a simple way to generate states that closely approximate Werner states, which have a controllable degree of entanglement.
    • Experimentally testing Hardy’s theorem on nonlocality with entangled mixed states*

      • Fan, Dai-He; Dai, Mao-Chun; Guo, Wei-Jie; Wei, Lian-Fu, Chinese Physics B 26, 40302 (2017)
      • https://dx.doi.org/10.1088/1674-1056/26/4/040302
      • Hardy’s theorem on nonlocality has been verified by a series of experiments with two-qubit entangled pure states. However, in this paper we demonstrate the experimental test of the theorem by using the two-photon entangled mixed states. We first investigate the generic logic in Hardy’s proof of nonlocality, which can be applied for arbitrary two-qubit mixed polarization entangled states and can be reduced naturally to the well-known logic tested successfully by the previous pure state experiments. Then, the optimized violations of locality for various experimental parameters are delivered by the numerical method. Finally, the logic argued above for testing Hardy’s theorem on nonlocality is demonstrated experimentally by using the mixed entangled-photon pairs generated via pumping two type-I BBO crystals. Our experimental results shows that Hardy’s proof of nonlocality can also be verified with two-qubit polarization entangled mixed states, with a violation of about 3.4 standard deviations.
    • Quantum optics and nano-optics teaching laboratory for the undergraduate curriculum: teaching quantum mechanics and nano-physics with photon counting instrumentation

      • Lukishova, Svetlana G., 14th Conference on Education and Training in Optics and Photonics: ETOP 2017 10452, 508-527 (2017)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10452/104522I/Quantum-optics-and-nano-optics-teaching-laboratory-for-the-undergraduate/10.1117/12.2269872.full
      • At the Institute of Optics, University of Rochester (UR), we have adapted to the main challenge (the lack of space in the curriculum) by developing a series of modular 3-hour experiments and 20-min-demonstrations based on technical elective, 4-credit-hour laboratory course “Quantum Optics and Nano-Optics Laboratory” (OPT 253/OPT453/PHY434), that were incorporated into a number of required courses ranging from freshman to senior level. Rochester Monroe Community College (MCC) students also benefited from this facility that was supported by four NSF grants. MCC students carried out two 3-hour labs on photon quantum mechanics at the UR. Since 2006, total 566 students passed through the labs with lab reports submission (including 144 MCC students) and more than 250 students through lab demonstrations. In basic class OPT 253, four teaching labs were prepared on generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach-Zehnder interferometer), (3) confocal microscope imaging of single-emitter (colloidal nanocrystal quantum dots and NV-center nanodiamonds) fluorescence within photonic (liquid crystal photonic bandgap microcavities) or plasmonic (gold bowtie nanoantennas) nanostructures, (4) Hanbury Brown and Twiss setup. Fluorescence antibunching from nanoemitters. Students also carried out measurements of nanodiamond topography using atomic force microscopy and prepared photonic bandgap materials from cholesteric liquid crystals. Manuals, student reports, presentations, lecture materials and quizzes, as well as some NSF grants’ reports are placed on a website http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/ . In 2011 UR hosted 6 professors from different US universities in three-days training of these experiments participating in the Immersion Program of the Advanced Laboratory Physics Association.
    • Quantum entanglement with Freedman's inequality

      • Brody, Jed; Selton, Charlotte, Am. J. Phys. 86, 412-416 (2018)
      • https://doi.org/10.1119/1.5036619
      • The assumption of local realism imposes constraints, such as Bell inequalities, on quantities obtained from measurements. In recent years, various tests of local realism have gained popularity in undergraduate laboratories, giving students the exciting opportunity to experimentally contradict this philosophical assumption. The standard test of the CHSH (Clauser–Horne–Shimony–Holt) Bell inequality requires 16 measurements, whereas a test of Freedman's inequality requires only three measurements. The calculations required to test Freedman's inequality are correspondingly simpler and the theory is less abstract. We suggest that students may benefit from testing Freedman's inequality before proceeding to the CHSH inequality and other more complicated experiments. Our measured data violated Freedman's inequality by more than six standard deviations.
    • Spontaneous parametric down-conversion

      • Couteau, Christophe, Contemporary Physics 59, 291-304 (2018)
      • https://doi.org/10.1080/00107514.2018.1488463
      • Spontaneous Parametric Down-Conversion (SPDC), also known as parametric fluorescence, parametric noise, parametric scattering and all various combinations of the abbreviation SPDC, is a non-linear optical process where a photon spontaneously splits into two other photons of lower energies. One would think that this article is about particle physics and yet it is not, as this process can occur fairly easily on a day to day basis in an optics laboratory. Nowadays, SPDC is at the heart of many quantum optics experiments for applications in quantum cryptography, quantum simulation, quantum metrology but also for testing fundamentals laws of physics in quantum mechanics. In this article, we will focus on the physics of this process and highlight a few important properties of SPDC. There will be two parts: a first theoretical one showing the particular quantum nature of SPDC, and the second part, more experimental and in particular focusing on applications of parametric down-conversion. This is clearly a non-exhaustive article about parametric down-conversion as there is a tremendous literature on the subject, but it gives the necessary first elements needed for a novice student or researcher to work on SPDC sources of light.
    • An undergraduate laboratory study of the polarisation of annihilation photons using Compton scattering

      • Knights, P.; Ryburn, F.; Tungate, G.; Nikolopoulos, K., Eur. J. Phys. 39, 45202 (2018)
      • https://dx.doi.org/10.1088/1361-6404/aab334
      • An experiment for the advanced undergraduate laboratory which allows students to study the effect of photon polarisation in Compton scattering and to explore quantum entanglement is described. The quantum entangled photons are produced through electron–positron annihilation in the S-state, and their polarisations are analysed using the Compton scattering cross-section dependence on the photon polarisation. The experiment was equipped with off-the-shelf detectors and electronic units. Finite geometry effects are discussed and investigated with the use of a Geant4-based simulation.
    • A simple technique for measuring the spatial correlation of photon pairs for complete interference in the Michelson interferometer

      • Boonkham, K.; Limsuwan, P., Journal of Physics: Conference Series 1380, 12043 (2019)
      • https://dx.doi.org/10.1088/1742-6596/1380/1/012043
      • In this research, a simple technique for measuring the spatial correlation or angular correlation of photon pairs was developed. The system consisted of two aluminium rails which had the same pivot at the position of a nonlinear crystal. The rails were manually moved to find the position of the correlated photon pairs. At this position, the photon pairs were collected by the collimators attached at the end of the rails. The pairs were produced by type I spontaneous parametric down-conversion process using a 405 nm diode laser and a BBO crystal. The crystal was specifically cut for emitting the photon pairs at an angle of 3° with respect to the direction of the pump laser. These pairing photons were correlated and interfered in the Michelson interferometer, then, the correlated photons were demonstrated. It was found that the visibilities in the case of perfect alignment, near perfect alignment and misalignment were V = 1.0000 ± 0.0004, 0.869 ± 0.002, 0.591 ± 0.002 and 0.168 ± 0.002, respectively.
    • A time-energy delayed-choice interference experiment for the undergraduate laboratory

      • Castrillón, Jhonny; Galvez, Enrique J.; Rodriguez, Boris A.; Calderón-Losada, Omar, Eur. J. Phys. 40, 55401 (2019)
      • https://dx.doi.org/10.1088/1361-6404/ab2afc
      • Laboratory experiments that illustrate the fundamentals of quantum physics are powerful teaching instruments because they re-enact thought experiments, allowing students to think deeper about the quantum-mechanical principles involved. Interference, wave–particle duality and entanglement are among the most important predictions of quantum mechanics. They are abstract and counter-intuitive. More recent concepts that help illustrate these subtleties include quantum erasure and delayed choice. In this article we present an experiment for the undergraduate laboratory that involves all of these issues or concepts. The experiment entails only minor modifications to a well-known setup for doing single-photon interference. In this article we present the experiment, its results and a theoretical description.
    • Quantum optics laboratories for teaching quantum physics

      • Galvez, Enrique J., Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019 11143, 312-318 (2019)
      • https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11143/111431A/Quantum-optics-laboratories-for-teaching-quantum-physics/10.1117/12.2523843.full
      • With the coming of quantum information and associated technologies, there is increasing need to prepare students on the fundamentals of quantum physics. Fundamental physical principles can be hidden by the mathematical formalism of quantum mechanics. Thus it is necessary to expose students to experiments that illustrate fundamentals. Quantum optics experiments based on the generation of twin photons via spontaneous parametric down-conversion have many advantages, such as being simple, reliable, and of reasonable cost. These types of experiments are ideal for the advanced laboratory in the physics curriculum. At Colgate University we offer them as a laboratory package that is associated with our upper-level undergraduate course on quantum mechanics. In this article we present our latest approaches. Among them is a new layout for the experiments to provide a more intuitive physical picture.
    • Simple experimental setup for producing polarization-entangled photons

      • Rojpattanakul, W.; Bongkodmalee, T.; Boonkham, K., Journal of Physics: Conference Series 1380, 12023 (2019)
      • https://dx.doi.org/10.1088/1742-6596/1380/1/012023
      • Quantum entanglement is an important action in quantum mechanics. Basically, quantum entanglement of correlated photon pairs can be produced by spontaneous down-conversion process inside the two birefringence crystals. This work aims to create a pair of photons, i.e. signal and idler, that are entangled and to assay the relation between these photons by using polarization-entangled photon pairs to demonstrate quantum non-locality by comparing with the Malus’s law. From the experiments, the coincidence counts as a function of relative angle (α - β) between transmission axis of the polarizer and analyzer were obtained and the polarization entanglement curve was demonstrated. This result corresponding with polarization entanglement prediction term of ½ cos2 (α - β) which confirmed the entanglement of photons.
    • Assessing randomness with the aid of quantum state measurement

      • Coleman, Mathew R.; Ingalls, Kaylin G.; Kavulich, John T.; Kemmerly, Sawyer J.; Salinas, Nicolas C.; Ramirez, Efrain Venegas; Schlosshauer, Maximilian, Am. J. Phys. 88, 238-246 (2020)
      • https://doi.org/10.1119/10.0000383
      • Randomness is a valuable resource in science, cryptography, engineering, and information technology. Quantum-mechanical sources of randomness are attractive because of the indeterminism of individual quantum processes. Here, we consider the production of random bits from polarization measurements on photons. We first present a pedagogical discussion of how the quantum randomness inherent in such measurements is connected to quantum coherence, and how it can be quantified in terms of the quantum state and an associated entropy value known as min-entropy. We then explore these concepts by performing a series of single-photon experiments that are suitable for the undergraduate laboratory. We prepare photons in different nonentangled and entangled states, and measure these states tomographically. We use the information about the quantum state to determine, in terms of the min-entropy, the minimum amount of randomness produced from a given photon state by different bit-generating measurements. This is helpful in assessing the presence of quantum randomness and in ensuring the quality and security of the random-bit source.
    • Single photon beat note in an acousto-optic modulator-based interferometer

      • Mathevet, Renaud; Chalopin, Benoit; Massenot, Sébastien, Am. J. Phys. 88, 313-318 (2020)
      • https://doi.org/10.1119/10.0000299
      • We present in the following a quantum optics experiment appropriate for advanced undergraduate students with former experience in quantum optics. It extends classical single photon setups to the time dependent domain. We demonstrate self-heterodyning of heralded single photons using a Mach-Zehnder like interferometer where beamsplitters are replaced by two acousto-optic modulators (AOMs). The single photon beat note is recorded over time at the frequency difference between the RF generators driving the AOMs, which makes it observable directly on a human time scale, i.e., with periods above a fraction of a second. To compare with our observations, we tailor the standard quantum optics formalism for beam splitters to take into account the frequency shifts associated with the AOMs.
    • A demonstration of quantum key distribution with entangled photons for the undergraduate laboratory

      • Bista, Aayam; Sharma, Baibhav; Galvez, Enrique J., Am. J. Phys. 89, 111-120 (2021)
      • https://doi.org/10.1119/10.0002169
      • Now that fundamental quantum principles of indeterminacy and measurement have become the basis of new technologies that provide secrecy between two communicating parties, there is a need to provide teaching laboratories that illustrate how these technologies work. In this article, we describe a laboratory exercise in which students perform quantum key distribution with single photons, and see how the secrecy of the communication is ensured by the principles of quantum superposition and state projection. We used a table-top apparatus, similar to those used in correlated-photon undergraduate laboratories, to implement the Bennett-Brassard-84 protocol with polarization-entangled photons. Our experiment shows how the communication between two parties is disrupted by an eavesdropper. We use a simple quartz plate to mimic how an eavesdropper intercepts, measures, and resends the photons used in the communication, and we analyze the state of the light to show how the eavesdropper changes it.
    • The Original Bell Theorem without Calculus

      • Brody, Jed, The Physics Teacher 59, 258-259 (2021)
      • https://doi.org/10.1119/10.0004150
      • Bell’s theorem is a topic of perennial fascination. Publishers and the general public have a steady appetite for approachable books about its implications. The scholarly literature includes many analogies to Bell’s theorem and simple derivations of Bell inequalities, and some of these simplified discussions are the basis of interactive web pages. Less well known is that the original Bell theorem is virtually unaffected when the calculus is taken away. Indeed, the only use of integrals in Bell’s derivation is to compute averages. We can simply replace integrals with the word “average.” The resulting proof of Bell’s theorem is just as easy to understand, and just as shocking, as the analogies designed to ease comprehension.
    • Seeing quantum mechanics: The role of quantum experiments

      • Borish, Victoria; Werth, Alexandra; Lewandowski, H. J., 2022 PHYSICS EDUCATION RESEARCH CONFERENCE (PERC) , 57-63 (2022)
      • https://doi.org/10.1119/perc.2022.pr.Borish
      • The second quantum revolution has prompted not only research in quantum science and technology, but also research on how best to educate students who may enter this burgeoning field. Much of the conversation around quantum science education has focused on students' conceptual learning or skills desired by potential employers; there has been an absence of work understanding how laboratory courses and experiments contribute to undergraduate quantum education. To begin understanding the role quantum experiments may play, we surveyed instructors who implement experiments with single and entangled photons in undergraduate lab courses and found that one of the most important learning goals was to "see quantum mechanics in real life." To better understand this goal, we interviewed 15 of the surveyed instructors asking what seeing quantum mechanics means to them and why they believe it is an important part of students' education. We present emergent themes from a qualitative coding analysis of these interviews, which begin to elucidate how instructors think about seeing quantum mechanics and what learning goals instructors hope seeing quantum mechanics-and working with quantum experiments more generally-will help students achieve.
    • Fifteen years of quantum optics, quantum information, and nano-optics educational facility at the Institute of Optics, University of Rochester

      • Lukishova, Svetlana G., Optical Engineering 61, 81811 (2022)
      • https://doi.org/10.1117/1.OE.61.8.081811
      • The quantum optics/quantum information and nano-optics educational laboratory facility (QNOL) at the University of Rochester (UR) is located within three rooms of the Institute of Optics with a total area of 587 ft2. It has been used for teaching a 4-credit-hour QNOL class annually for 15 years. Four teaching labs were prepared on the generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach–Zehnder interferometer), (3) single-photon source I: confocal fluorescence microscopy of single nanoemitters, and (4) single-photon source II: a Hanbury Brown and Twiss setup, fluorescence antibunching. Further, based on QNOL, 1.5 to 3 h sturdy quantum “mini-labs” were developed and introduced into the required classes such that all optics students at the UR had experience with quantum labs. Monroe Community College (MCC) students participated in two mini-labs at the UR. Since 2006 to spring 2022, a total of ~850 students have utilized the labs for lab report submission (including 144 MCC students) and more than 250 students have used them for lab demonstrations. In addition, UR freshman research projects have become a very important educational activity in this facility. All developed materials and students’ reports are available at http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/. We present a description of sturdy, universally accessible experiments that can be introduced into either a separate advanced class or into classes with a large number of students. Assessment methods, evaluation of students’ knowledge, and their attitude toward their career in quantum information are discussed.
    • Implementation and goals of quantum optics experiments in undergraduate instructional labs

      • Borish, Victoria; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 19, 10117 (2023)
      • https://link.aps.org/doi/10.1103/PhysRevPhysEducRes.19.010117
      • As quantum information science and technology (QIST) is becoming more prevalent and occurring not only in research labs but also in industry, many educators are considering how best to incorporate learning about quantum mechanics into various levels of education. Although much of the focus has been on quantum concepts in nonlab courses, current work in QIST has a substantial experimental component. Many instructors of undergraduate lab courses want to provide their students the opportunity to work with quantum experiments. One common way this is done is through a sequence of quantum optics experiments often referred to as the “single-photon experiments.” These experiments demonstrate fundamental quantum phenomena with equipment common to research labs; however, they are resource intensive and cannot be afforded by all institutions. It is therefore imperative to know what unique affordances these experiments provide to students. As a starting point, we surveyed and interviewed instructors who use the single-photon experiments in undergraduate courses, asking how and why they use the experiments. We describe the most commonly used experiments in both quantum and beyond-first-year lab courses, the prevalence of actions the students perform, and the learning goals, ranging from conceptual knowledge to lab skills to student affect. Finally, we present some strategies from these data demonstrating how instructors have addressed the common challenges of preparing students to work with conceptually and technically complex experiments and balancing the practice of technical skills with the completion of the experiments.
    • Seeing quantum effects in experiments

      • Borish, Victoria; Lewandowski, H. J., Phys. Rev. Phys. Educ. Res 19, 20144 (2023)
      • https://doi.org/10.1103/PhysRevPhysEducRes.19.020144
      • [This paper is part of the Focused Collection on Instructional labs: Improving traditions and new directions.] Quantum mechanics is a field often considered very mathematical, abstract, and unintuitive. One way some instructors are hoping to help familiarize their students with these complex topics is to have the students see quantum effects in experiments in undergraduate instructional labs. Here, we present results from an interview study about what it means to both instructors and students to see quantum effects in experiments. We focus on a popular set of quantum optics experiments and find that students believe they are observing quantum effects and achieving related learning goals by working with these experiments. Although it is not possible to see the quantum phenomena directly with their eyes, students point out different aspects of the experiments that contribute to them observing quantum effects. This often includes seeing the experimental results, sometimes in conjunction with interacting with or understanding part of the experiment. There is additional variation across student achievement of the various related learning goals, ranging from many of the students being excited about these experiments and making a connection between the mathematical theory and the experiments to only some of the students seeing a connection between these experiments and quantum technologies. This work can help instructors consider the importance and framing of quantum experiments and raises questions about when and how in the curriculum quantum experiments can be best utilized and how to make related learning goals available to all students., This article appears in the following collection:
    • Quantum Mechanics in a quicker, more intuitive, and accessible way

      • Deveney, Edward; Demirbas, Elif; Serna, Samuel, Seventeenth Conference on Education and Training in Optics and Photonics: ETOP 2023 (2023), paper 1272334 , 1272334 (2023)
      • https://doi.org/10.1117/12.2670760
      • Quantum Mechanics in the headlines today captures the imagination of the public, deep wallets of investors and industries, and prioritizes academic and national research programs throughout the world. It all begins with superposition and entanglement. Canonical educational approaches, however, may not build the intuitive or the computational ability required of practitioners where quantum is center-stage. An APS News front-page article by Meredith Fore details and explores the current situation: ”The Newest Frontier: Building a Skilled workforce. Education in Quantum Mechanics has lagged for years. Experts are trying to change this.”1 Here we highlight innovations and experiences coupling our curriculum, advanced labs, and undergraduate research to best address these educational questions and skills-based needs. Our approaches are based on ready-available two-state, two-particle entangled light source table-top experiments and finite-dimensioned (familiar) vector spaces as opposed to infinitely dimensioned function-space solutions to differential equations with little intuitive connection and/or easy access to experimental experience. Our Physics and Photonics and Optical Engineering Quantum I course has migrated from a traditional text to one espousing these new directions (M. Beck. Quantum Mechanics, Theory and Experiment)2 and our experiments are centered around a commercially available educational entanglement source (Quantum Design, quTool’s quED)3 with avalanche single-photon detectors, coincidence electronics, with standard and add-on experiments that are in step with the text but, as a kit, come more student-ready. This approach may better promote quantum technologies, prepare scientists, technicians, and engineers, and offer deeper insight to what quantum is really telling us.
    • A Curriculum of Table-Top Quantum Optics Experiments to Teach Quantum Physics

      • Galvez, E. J., Journal of Physics: Conference Series 2448, 12006 (2023)
      • https://dx.doi.org/10.1088/1742-6596/2448/1/012006
      • The rise of quantum information as a viable technology requires appropriate instructional curricula for preparing a future workforce. Key concepts that are the basis of quantum information involve fundamentals of quantum mechanics, such as superposition, entanglement and measurement. To complement modern initiatives to teach quantum physics to the emerging workforce, lab experiences are needed. We have developed a curriculum of quantum optics experiments to teach quantum mechanics fundamentals and quantum algebra. These laboratories provide hands-on experimentation of optical components on a table-top. We have also created curricular materials, manuals, tutorials, parts and price lists for instructors. Automation of the apparatus offers the flexibility of using the apparatus remotely and for giving access to a greater number of students with a single setup.
    • Quantum Optics Laboratories with Motorized Components

      • Galvez, Enrique J., Seventeenth Conference on Education and Training in Optics and Photonics: ETOP 2023 (2023), paper 127232Z , 127232Z (2023)
      • https://opg.optica.org/abstract.cfm?uri=ETOP-2023-127232Z
      • Quantum optics laboratories are emerging as suitable educational platforms to complement quantum mechanics instruction and expose students to non-traditional demonstrations of quantum physics involving quantum superposition and measurement. The automation of these experiments offers an interesting alternative paradigm. In this contribution, I present the automation of laboratory experiments through motorized mounts that displace or rotate optical components, enabling remote execution of the experiments. Some additional benefits include improved repeatability and better preparation of photonic quantum states.
    • Sustainable education in the age of the second quantum revolution: fifteen years of the University of Rochester National Science Foundation supported efforts

      • Lukishova, Svetlana G.; Bigelow, Nicholas, Seventeenth Conference on Education and Training in Optics and Photonics: ETOP 2023 (2023), paper 127230B , 127230B (2023)
      • https://doi.org/10.1117/12.2666502
      • Quantum optics/quantum information and nano-optics educational laboratory facility (QNOL) at the University of Rochester (UR) is located within three rooms of the Institute of Optics with a total area of 587 ft2. Four teaching labs were prepared on the generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell’s inequalities, (2) single-photon interference (Young’s double slit experiment and Mach-Zehnder interferometer), (3) single-photon source I: confocal fluorescence microscopy of single nanoemitters, and (4) single-photon source II: a Hanbury Brown and Twiss setup, fluorescence antibunching. We also describe a coherent undergraduate educational program in nanoscience/nanoengineering at the UR based on the QNOL and Integrated Nanosystems Center resources. From 2006 to May 2023, a total of ~900 students have utilized the quantum/nano labs for lab report submission (including 144 Monroe Community College students) and more than 300 students have used them for lab demonstrations. These two projects have three main outcomes: (1) developing a curriculum and offering the Certificate in Nanoscience and Nanoengineering; (2) creating an exemplary model of collaboration in quantum/nanotechnology between a university with state-of-the-art, expensive experimental facilities and a nearby two-year community college; and (3) developing universally accessible “hands-on” experiments (minilabs) on quantum/nanophotonics, learning materials, and pedagogical methods. The inexpensive mini-labs described herein can be adopted in small colleges. All developed materials and students’ reports are available at http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/. Two papers in a special issue of Optical Engineering describe these two programs with more details: https://doi.org/10.1117/1.OE.61.8.081811 and https://doi.org/10.1117/1.OE.61.8.081810.
    • Unexpected optimal measurement protocols in Bell's inequality violation experiments

      • Negre, Alicia; Mathevet, Renaud; Chalopin, Benoit; Massenot, Sébastien, Am. J. Phys. 91, 64-73 (2023)
      • https://doi.org/10.1119/5.0102516
      • Bell's inequality violation experiments are becoming increasingly popular in the practical teaching of undergraduate and master's degree students. Bell's parameter S is obtained from 16 polarization correlation measurements performed on entangled photons pairs. We first report here a detailed analysis of the uncertainty u(S) of Bell's parameter taking into account coincidence count statistics and errors in polarizers' orientation. We show using both computational modeling and experimental measurement that the actual sequence of the polarizer settings has an unexpected and strong influence on the error budget. This result may also be relevant to measurements in other settings in which errors in parameters may have non-random effects in the measurement.
  • solid state

    • An Advanced Laboratory Experiment on Tunneling in Semiconductor Diodes

      • Merrill, J. R., Am. J. Phys. 37, 269-272 (1969)
      • https://doi.org/10.1119/1.1975502
      • This paper deals with an advanced laboratory experiment on tunneling mechanisms in tunnel diodes. The experiment measures phonon-assisted tunneling in silicon tunnel diodes. Student data are shown; the results agree nicely with previous data in the literature and with band structure calculations for Si. The student learns about band structure, phonons, tunneling techniques, and differentiation, techniques.
    • Superconductive Tunneling in the Advanced Laboratory

      • Merrill, J. R.; Christy, R. W., Am. J. Phys. 37, 61-64 (1969)
      • https://doi.org/10.1119/1.1975406
      • This paper reports an experiment for an advanced laboratory. The experiment concerns superconductive tunneling measurements of the variation of the energy gap in lead with temperature. The tunneling occurs between evaporated aluminum and evaporated lead films which are separated by an aluminum oxide insulator. The experiment is performed by dipping the samples into a liquid-helium storage Dewar and uses very little helium. The measurements include the variation of the energy gap in lead between 4.2°K and the transition temperature of the lead film. Student data are used in the figures.
    • Ferroelectricity Experiment for Advanced Laboratory

      • Schmidt, V. Hugo, Am. J. Phys. 37, 351-354 (1969)
      • https://doi.org/10.1119/1.1975572
      • An experiment suitable for a junior or senior physics laboratory is described, in which the spontaneous polarization and coercive field for Rochelle salt are measured from the ferroelectric hysteresis loops, over the temperature range −18° to +24°C in which this crystal is ferroelectric. The suitability of triglycine sulfate for this experiment is discussed. The apparatus is also useful in demonstrating the relation of capacitance to electrode geometry, and in determining dielectric constants.
    • Thermoelectric Power Experiment for the Advanced Laboratory

      • Greenslade, Thomas B., Jr., Am. J. Phys. 38, 480-486 (1970)
      • https://doi.org/10.1119/1.1976370
      • Apparatus suitable for measurements of the thermoelectric power of wires in the temperature region from 77 to 300 K is described. An outline of the theoretical treatment of thermoelectric power is presented and typical results are given for aluminum, gold, and iron. This experiment has been used in the undergraduate advanced laboratory.
    • Kohlrausch Heat Conductivity Apparatus for Intermediate or Advanced Laboratory

      • Jensen, H. G., Am. J. Phys. 38, 870-874 (1970)
      • https://doi.org/10.1119/1.1976485
      • A student experiment in measuring heat conductivity according to Kohlrausch's method is described. Theory, apparatus design, and experimental procedure are outlined. Results for copper are consistent to within 2%. Measurements may be accomplished in one or two laboratory sessions (6–8 h).
    • A Helicon Solid-State Plasma Experiment for the Advanced Laboratory

      • Merrill, J. R.; Pierce, D.; Giovanielli, D., Am. J. Phys. 38, 417-421 (1970)
      • https://doi.org/10.1119/1.1976357
      • This paper reports an advanced undergraduate laboratory experiment concerning the helicon solid-state plasma wave. Student results are reported. The experiment is performed as an inexpensive dip in a liquid helium storage vessel. The experiment is made possible by the design of a small, superconducting magnet. The magnet is capable of attaining 18 kG and costs about $25. The whole experiment can be built by students in a week's time. When the experiment is completed, the student not only understands helicon propagation but also understands the use of the helicon to measure magnetoresistance and Hall coefficients in pure metals.
    • Superconductivity in the advanced laboratory

      • Behroozi, F.; King, K. R., Am. J. Phys. 44, 1187-1191 (1976)
      • https://doi.org/10.1119/1.10259
      • Two simple experiments in superconductivity suitable for the advanced undergraduate laboratory are described. A homemade variable‐frequency oscillator is employed in a conventional cryostat to measure the superconducting transition temperature of tin using a resonant‐tank‐circuit method. The setup is further used to obtain the superconducting–normal phase diagram for tin in the presence of a magnetic field. Enough experimental details are provided to enable a nonspecialist to duplicate the setup and perform the experiments.
    • The physics of electrochromism: An advanced laboratory experiment

      • Peterson, C. W.; Parlett, J.; Crandall, R. S., Am. J. Phys. 47, 772-775 (1979)
      • https://doi.org/10.1119/1.11926
      • Amorphous tungsten trioxide films offer an interesting electrochromic system whose properties are readily amenable to study in a senior undergraduate laboratory. Basic optical color center properties, and electron and proton diffusion processes are characterized for the HxWO3 produced; additional experiments including the variation of the chemical potential of the hydrogen component and low‐temperature exploration of the metal‐insulator transition are proposed for the advanced student. The samples are easily prepared and measured by elementary means. The broad solid‐state concepts involved enrich standard advanced laboratory repertoires of more conventional nuclear and NMR experiments.
    • Advanced undergraduate laboratory experiment in inelastic electron tunneling spectroscopy

      • White, H. W.; Graves, R. J., Am. J. Phys. 50, 38-41 (1982)
      • https://doi.org/10.1119/1.12984
      • An advanced undergraduate laboratory experiment in inelastic electron tunneling spectroscopy is described. The project was done by junior‐ and senior‐level students. Tunnel junctions were fabricated, the tunneling spectra of several molecules adsorbed on the surface of aluminum oxide measured, and mode assignments made for several of the prominent peaks in the spectra using results obtained from optical studies.
    • Magnetic behavior of superconductors: An experiment for the advanced laboratory

      • Behroozi, F., Am. J. Phys. 51, 28-32 (1983)
      • https://doi.org/10.1119/1.13414
      • Superconductivity holds a special appeal to undergraduates and can provide fascinating and instructive experiments in the advanced laboratory. Here we discuss a convenient method to obtain the magnetization curves of superconductors and use the method to study the diamagnetic behavior of tin and vanadium as representatives of the two types of superconductors.
    • F‐centers: advanced laboratory experiments as a ‘‘research project’’

      • Reichert, Jonathan F., Am. J. Phys. 51, 431-433 (1983)
      • https://doi.org/10.1119/1.13231
      • A sophomore physics laboratory project is described which experimentally and theoretically studies by optical absorption bands of F‐centers in alkali halide crystals using a variety of instrumental techniques. The student is challenged to develop a theoretical model to describe the optical absorption data.
    • Characterization of a bulk semiconductor’s band gap via a near‐absorption edge optical transmission experiment

      • Essick, John M.; Mather, Richard T., Am. J. Phys. 61, 646-649 (1993)
      • https://doi.org/10.1119/1.17173
      • An experimental setup that employs lock‐in detection to measure the optical transmission data on a bulk semiconductor sample is described. A straightforward manipulation of these data yields the semiconductor’s absorption coefficient α in the energy range near its absorption edge (0<α<100 cm−1). The theory of optical transitions in semiconductors required to analyze the resulting absorption spectra is presented. It is shown that a model based on an indirect optical transition involving a single phonon accurately describes data taken on a silicon sample. Based on this analysis, a value of (1.098±0.004) eV for silicon’s indirect band gap and an energy of (51±4) meV for the involved phonon is deduced. Conversely, it is shown that data taken on a gallium–arsenide sample are consistent with a model based on a direct optical transition involving exponential band‐tail states. A value for the band‐tail’s Urbach slope of E0=(6.7±0.2) meV is found. All of these results accurately agree with published values. This laboratory demonstrates important concepts in solid state physics via universally applicable experimental techniques at a level appropriate for upper‐division undergraduates.
    • Critical current density of YBa2Cu3O7−x

      • Oldenburg, K. E.; Morrison, W. A.; Brown, G. C., Am. J. Phys. 61, 832-834 (1993)
      • https://doi.org/10.1119/1.17414
      • An experiment to determine the critical current density of superconducting YBa2Cu3O7−x is described. The experiment has been used in a solid state physics course and would also be suitable for modern physics or advanced laboratory courses as well as for courses in physical or inorganic chemistry.
    • Micro‐Raman spectroscopy in the undergraduate research laboratory

      • Voor, R.; Chow, L.; Schulte, A., Am. J. Phys. 62, 429-434 (1994)
      • https://doi.org/10.1119/1.17544
      • Modern materials science requires processing and characterization techniques for microscopic structures. Molecular probes such as Raman spectroscopy are some of the most viable tools, particularly if they are supplemented by imaging to obtain spatially resolved compositional information of inhomogeneous or low volume samples. In order to introduce these techniques and materials science experiments into the advanced undergraduate laboratory, we have constructed an inexpensive micro‐Raman attachment, which consists of an off‐the‐shelf microscope and the coupling optics to an existing Raman spectrometer. The modification of the microscope, the optical coupling, and a low cost viewing system for positioning the laser excitation on the sample are described in detail. The students study molecular spectra of new materials such as diamond films, Fullerenes, and biological compounds with spatial resolution of several microns.
    • Measurement of the ratio h/e2 in an advanced undergraduate laboratory

      • Schober, A. M.; Ruedlinger, B.; Dahm, A. J., Am. J. Phys. 67, 524-527 (1999)
      • https://doi.org/10.1119/1.19317
      • The two-dimensional integer quantum Hall effect is shown to be a feasible experiment for an advanced undergraduate laboratory. A measurement of the ratio h/e2 yielded a value of 25 811(±1+4) Ω. The established value is 25 812.81 Ω. Techniques which would improve this accuracy to 15 ppm are suggested.
    • Measuring the interaction force between a high temperature superconductor and a permanent magnet

      • Valenzuela, S. O.; Jorge, G. A.; Rodrı́guez, E., Am. J. Phys. 67, 1001-1006 (1999)
      • https://doi.org/10.1119/1.19160
      • Repulsive and attractive forces are both possible between a superconducting sample and a permanent magnet, and they can give rise to magnetic levitation or free-suspension phenomena, respectively. We show experiments to quantify this magnetic interaction, which represents a promising field with regard to short-term technological applications of high temperature superconductors. The measuring technique employs an electronic balance and a rare-earth magnet that induces a magnetic moment in a melt-textured YBa2Cu3O7 superconductor immersed in liquid nitrogen. The simple design of the experiments allows a fast and easy implementation in the advanced physics laboratory with a minimum cost. Actual levitation and suspension demonstrations can be done simultaneously as a help to interpret magnetic force measurements.
    • A field emission microscope in an advanced students' laboratory

      • Greczylo, Tomasz; Mazur, Piotr; Dębowska, Ewa, Eur. J. Phys. 27, 265 (2006)
      • https://dx.doi.org/10.1088/0143-0807/27/2/009
      • This paper describes a university level experiment during which students can observe the surface structure and determine the work function of a clean single tungsten crystal and a crystal covered with barium. The authors used a commercial field emission microscope offered by Leybold Didactic and designed an experiment which can be easily reproduced and performed in a students' laboratory. The use of a digital camera and computer allowed simultaneous observation and imaging of the surface of the body-centred cubic structure of the single tungsten crystal. Some interesting results about the changes in tungsten work function with time and with barium coverage are presented and discussed. The data help to improve knowledge and skills in the calculation of measurement uncertainty.
    • An electrochromic film device to teach polymer electrochemical physics

      • Huang, Mei-Rong; Tao, Tao; Li, Xin-Gui; Gong, Qian-Cheng, Am. J. Phys. 75, 839-843 (2007)
      • https://doi.org/10.1119/1.2746365
      • We discuss the background associated with an electrochromic device that can reversibly change its color and. optical density at a specific potential. We discuss the underlying science needed to make a new polyaniline (PAN)/polyvinyl alcohol(PVA) electrochromic composite film on an indium-tin oxide (ITO) conducting glass by electropolymerization and describe a reversible redox transition of the PAN. The experiment gives students an opportunity to fabricate an electrochromic device containing PAN, one of the most important conducting polymers. The experimental conditions are flexible so that each group of students can construct their own electrochromic device with particular behavior. Two techniques for polymerizing the PAN and three methods of demonstrating the electrochromism are given, depending on the available apparatus. A sophisticated three-electrode potentiostat or a crude apparatus containing a battery, wire, a variable resistor, and a voltage meter is used to synthesize the PAN deposit. The electrochromic property is repetitively observed by reversibly changing the applied potentials on the device. A potentiostatic apparatus, a single flashlight battery, or a flashlight battery accompanied by a variable resistor allows students to observe multicolor electrochromism. The experiments significantly enhance students' understanding of polymer chemicophysics principles and their appreciation of novel variable colorful films. The experiments are safe and easy to perform, provided that appropriate precautions are taken. (c) 2007 American Association of Physics Teachers.
    • Resource Letter Scy-3: Superconductivity

      • Butch, N. P.; de Andrade, M. C.; Maple, M. B., Am. J. Phys. 76, 106-118 (2008)
      • https://doi.org/10.1119/1.2802574
      • This Resource Letter provides a guide to the literature on superconductivity. Since the last Resource Letter on superconductivity, Scy-2, was published in 1970, there have been dramatic advances in our basic understanding of superconductivity, discovery of new superconducting materials, and improved technological exploitation of superconductors. We review basic phenomenology, followed by concise descriptions of several main classes of superconductors recognized today. Journal articles and books are cited for the following topics: Conventional superconductors, paramagnetic impurities in superconductors, magnetically ordered superconductors, heavy fermion superconductors, high Tc superconductors, organic superconductors, applications of superconductivity, and laboratory demonstrations of superconductivity. Owing to the large volume of available literature on superconductivity, the journal articles and books we discuss constitute good starting points for further exploration of particular topics.
    • Undergraduate experiment in superconductor point-contact spectroscopy with a Nb/Au junction

      • Janson, Lucas; Klein, Matthew; Lewis, Heather; Lucas, Andrew; Marantan, Andrew; Luna, Katherine, Am. J. Phys. 80, 133-140 (2012)
      • https://doi.org/10.1119/1.3660665
      • We describe an experiment in superconductivity suitable for an advanced undergraduate laboratory. Point-contact spectroscopy is performed by measuring the differential conductance between an electrochemically etched gold tip and a 100-nm thick superconducting niobium film with a transition temperature Tc ≈ 7 K. By fitting the results to Blonder–Tinkham–Klapwijk theory using a finite lifetime of quasiparticles, we obtain a superconducting gap energy Δ ≈ 1.53 meV, a lower bound to the Fermi velocity vF ≥ 3.1 × 107 cm/s, and a BCS coherence length ξ ≈ 43 nm for niobium. These results are in good agreement with previous measurements.
    • One-dimensional light localization with classical scatterers: An advanced undergraduate laboratory experiment

      • Kemp, K. J.; Barker, S.; Guthrie, J.; Hagood, B.; Havey, M. D., Am. J. Phys. 84, 746-751 (2016)
      • https://doi.org/10.1119/1.4958615
      • The phenomenon of electronic wave localization through disorder remains an important area of fundamental and applied research. Localization of all wave phenomena, including light, is thought to exist in a restricted one-dimensional geometry. We present here a series of experiments to illustrate, using a straightforward experimental arrangement and approach, the localization of light in a quasi-one-dimensional physical system. In the experiments, reflected and transmitted light from a stack of glass slides of varying thickness reveals an Ohm's law type behavior for small thicknesses, and evolution to exponential decay of the transmitted power for larger thicknesses. For larger stacks of slides, a weak departure from one-dimensional behavior is also observed. The experiment and analysis of the results, showing many of the essential features of wave localization, is relatively straightforward, economical, and suitable for laboratory experiments at an undergraduate level. (C) 2016 American Association of Physics Teachers.
    • Introduction to semiconductor processing: Fabrication and characterization of p-n junction silicon solar cells

      • Smith, Ryan P.; Hwang, Angela An-Chi; Beetz, Tobias; Helgren, Erik, Am. J. Phys. 86, 740-746 (2018)
      • https://doi.org/10.1119/1.5046424
      • We describe an upper-division undergraduate physics laboratory experiment that integrates the fabrication and characterization of a p-n junction in silicon. Under standard illumination, this p-n junction exhibits the photovoltaic effect as well as the typical diode rectification behavior when measured in the dark. This experiment introduces students to the physics of solar photovoltaics from the perspective of participating in the fabrication process. Procedures, experimental strategies, and typical student measurement results are presented. This low-cost, engaging, and effective lab can be adapted to undergraduate physics courses at various institutes. (C) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.
    • Little bits of diamond: Optically detected magnetic resonance of nitrogen-vacancy centers

      • Zhang, Haimei; Belvin, Carina; Li, Wanyi; Wang, Jennifer; Wainwright, Julia; Berg, Robbie; Bridger, Joshua, Am. J. Phys. 86, 225-236 (2018)
      • https://doi.org/10.1119/1.5023389
      • We give instructions for the construction and operation of a simple apparatus for performing optically detected magnetic resonance measurements on diamond samples containing high concentrations of nitrogen-vacancy (NV) centers. Each NV center has a spin degree of freedom that can be manipulated and monitored by a combination of visible and microwave radiation. We observe Zeeman shifts in the presence of small external magnetic fields and describe a simple method to optically measure magnetic field strengths with a spatial resolution of several microns. The activities described are suitable for use in an advanced undergraduate lab course, powerfully connecting core quantum concepts to cutting edge applications. An even simpler setup, appropriate for use in more introductory settings, is also presented.
    • A z-axis tunneling microscope for undergraduate labs

      • Lindgren, Randy; Kozan, Wesley; Fuerst, Noah; Knapp, Douglas; Veazey, Joshua P., Am. J. Phys. 90, 795-800 (2022)
      • https://doi.org/10.1119/5.0094028
      • We present the design and construction of a laboratory apparatus that provides advanced undergraduates with hands-on observations of electron quantum tunneling and the electronic density of states of various materials. The instrument is inspired by the scanning tunneling microscope (STM), but its implementation is simplified by limiting the tip motion to the single dimension along the tip-sample separation (z-axis); we refer to the device as the z-axis tunneling microscope (ZTM). Students are able to use the ZTM to measure electron tunneling probability as a function of barrier width, estimate relative material work functions, and observe differences in local electronic structure among metals, semimetals, and semiconductors. We share results obtained by third-year undergraduate physics students using the instrument for their final projects in an advanced instructional lab course.
    • Making exciton physics easy and affordable

      • Xie, Yong; Ersu, Gulsum; Pucher, Thomas; Kuriakose, Sruthi; Zhang, Wenliang; Al-Enizi, Abdullah M.; Albrithen, Hamad A. H.; Nafady, Ayman; Bratschitsch, Rudolf; Island, Joshua O.; Castellanos-Gomez, Andres, Eur. J. Phys. 44, 55501 (2023)
      • https://dx.doi.org/10.1088/1361-6404/ace748
      • We present a facile and low-cost undergraduate laboratory experiment to study exciton physics. Using a simple abrasion technique to create samples of thin-film van der Waals material samples and a low-cost spectrometer, we show that prominent excitonic features can be easily resolved in the optical transmission spectra of semiconducting transition metal dichalcogenides at ambient conditions. Our method brings interesting semiconductor quasiparticle physics to low-budget departments, hoping to expand their undergraduate laboratory curriculum.
  • spectroscopy

    • Mössbauer-Effect Apparatus for an Advanced Undergraduate Teaching Laboratory

      • Bearden, Alan J.; Mattern, P. L.; Nobel, P. S., Am. J. Phys. 32, 109-119 (1964)
      • https://doi.org/10.1119/1.1970138
      • A Mössbauer-effect apparatus, suitable for either lecture demonstration or inclusion in an undergraduate teaching laboratory, is described. Use of a rotating tilted disk to provide linear motion between source and absorber simplifies the construction and calibration of the experimental equipment. Some features are as follows: calibration of velocity by timing rotations of the wheel with a stopwatch, provision of a large-scale motion which graphically illustrates the first-order relativistic Doppler shift and its effect on monochromatic radiation, and sufficient precision to measure the nuclear Zeeman splitting in iron of the Fe57m transition. Construction details, as well as instructions for the use of the equipment, are given.
    • Advanced Laboratory Experiments on Optical Pumping of Rubidium Atoms—Part I: Magnetic Resonance

      • Nagel, Michael; Haworth, F. E., Am. J. Phys. 34, 553-558 (1966)
      • https://doi.org/10.1119/1.1973111
      • The construction and operation of a simple apparatus for optical pumping experiments using rubidium vapor are described. The experiments are intended to involve students with the concepts of resonance, atomic orientation, nuclear magnetic moments, and the precession of atomic magnetic moments. An outline of the elementary theory is included.
    • Advanced Laboratory Experiments on Optical Pumping of Rubidium Atoms—Part II: Free Precession

      • Nagel, Michael; Haworth, F. E., Am. J. Phys. 34, 559-561 (1966)
      • https://doi.org/10.1119/1.1973112
      • A student experiment with free precession of rubidium atoms is described which uses the simple apparatus for optical pumping experiments described in Part I of this paper. This experiment shows that an oriented ensemble of atoms may be treated as a macroscopic magnetized gyroscope.
    • F‐centers: advanced laboratory experiments as a ‘‘research project’’

      • Reichert, Jonathan F., Am. J. Phys. 51, 431-433 (1983)
      • https://doi.org/10.1119/1.13231
      • A sophomore physics laboratory project is described which experimentally and theoretically studies by optical absorption bands of F‐centers in alkali halide crystals using a variety of instrumental techniques. The student is challenged to develop a theoretical model to describe the optical absorption data.
    • High‐resolution solar spectroscopy in the undergraduate physics laboratory

      • Ratcliff, Stephen J.; Noss, Darcy K.; Dunham, Jeffrey S.; Anthony, Eric B.; Cooley, John H.; Alvarez, Alberto, Am. J. Phys. 60, 645-649 (1992)
      • https://doi.org/10.1119/1.17119
      • The richness of the solar spectrum at visible wavelengths makes it ideally suited for many laboratory exercises in optical spectroscopy. A number of such experiments taking advantage of a high‐resolution scanning spectrometer are described as they have been performed by seniors at Middlebury College. Physical principles emphasized include optical depth, the nature of molecular spectra, the Doppler effect, and the Zeeman effect. These experiments are suitable for advanced undergraduate physics and astronomy majors.
    • Experimental verification of the Heisenberg uncertainty principle—An advanced undergraduate laboratory

      • DeYoung, P. A.; Jolivette, P. L.; Rouze, N., Am. J. Phys. 61, 560-563 (1993)
      • https://doi.org/10.1119/1.17209
      • The Heisenberg uncertainty principle can be experimentally demonstrated by combining a Mössbauer experiment with a measurement of a nuclear lifetime. The senior undergraduate students perform a Mössbauer experiment to measure the energy width of the 14.4 keV level of 57Fe followed by measurements of coincident γ rays to determine the lifetime of the level. The experiments are designed to emphasize that the uncertainty principle is inherent in the wave function rather than resulting from the measurement process.
    • Micro‐Raman spectroscopy in the undergraduate research laboratory

      • Voor, R.; Chow, L.; Schulte, A., Am. J. Phys. 62, 429-434 (1994)
      • https://doi.org/10.1119/1.17544
      • Modern materials science requires processing and characterization techniques for microscopic structures. Molecular probes such as Raman spectroscopy are some of the most viable tools, particularly if they are supplemented by imaging to obtain spatially resolved compositional information of inhomogeneous or low volume samples. In order to introduce these techniques and materials science experiments into the advanced undergraduate laboratory, we have constructed an inexpensive micro‐Raman attachment, which consists of an off‐the‐shelf microscope and the coupling optics to an existing Raman spectrometer. The modification of the microscope, the optical coupling, and a low cost viewing system for positioning the laser excitation on the sample are described in detail. The students study molecular spectra of new materials such as diamond films, Fullerenes, and biological compounds with spatial resolution of several microns.
    • Analysis of idealized Zeeman quantum beat experiments in the advanced laboratory

      • Gemmen, G. J.; Rouze, N., Am. J. Phys. 64, 147-150 (1996)
      • https://doi.org/10.1119/1.18134
      • An expression for the time-dependent intensity of light scattered in idealized Zeeman quantum beat experiments commonly found in advanced teaching laboratories is presented. The development of this expression illustrates the separation of geometrical and dynamical factors via the Wigner-Eckart theorem. The experiment is also interpreted in terms of a pictorial description of a rotating electron cloud, and an experimental procedure to illustrate this rotation is described. (C) 1996 American Association of Physics Teachers.
    • Scanning, spherical-mirror Fabry-Perot interferometer: An upper-division optics laboratory experiment

      • Nachman, P.; Bernstein, A. C., Am. J. Phys. 65, 202-213 (1997)
      • https://doi.org/10.1119/1.18572
      • Students in our upper-division/graduate physical optics laboratory course assemble a high-finesse Fabry-Perot interferometer (FPI) from components, mode-match it to a helium-neon (HeNe) laser, and examine some of the FPI system's properties and uses. Here, we specify the necessary equipment and describe experimental procedures. For example, the experiments use the FPI's high spectral resolution to monitor the laser's behavior as it warms up; in another experimental step, they confront the issue of the photodetection system's electronic bandwidth. We also provide a review of Gaussian beam formulas and detail their use in mode-matching calculations. (C) 1997 American Association of Physics Teachers.
    • A modular, reconfigurable-cavity, pulsed dye laser for the advanced undergraduate laboratory

      • Sohl, J. E.; Payton, S. G., Am. J. Phys. 65, 640-652 (1997)
      • https://doi.org/10.1119/1.18621
      • The modular pulsed dye laser described is extremely easy to build, is quickly reconfigurable into different laser cavity designs, and is usable for experiments in spectroscopy. The laser can be constructed with readily available optical components and simple hand tools. This laser is designed primarily to illustrate the performance differences of three different dye laser cavity designs: the Littrow grating (Hansch) cavity, and both the single- and double-grating grazing incidence cavities. In the double-grating configuration, the laser's linewidth of 0.007 nm is on the order of ten times narrower than many commercially available pulsed dye lasers. Thus the laser also has excellent performance as a spectroscopic tool. Construction, typical performance, and application details are described. (C) 1997 American Association of Physics Teachers.
    • Nonlinear laser spectroscopy and magneto-optics

      • Budker, Dmitry; Orlando, Donald J.; Yashchuk, Valeriy, Am. J. Phys. 67, 584-592 (1999)
      • https://doi.org/10.1119/1.19328
      • An experiment on nonlinear laser spectroscopy and magneto-optics at the Advanced Undergraduate Laboratory at Berkeley is described. The experiment consists of three parts. In the first part, students learn to operate a diode laser system and characterize its performance using a Fabry–Perot spectrum analyzer. In the second part, Doppler-broadened laser-induced fluorescence and Doppler-free saturated absorption spectra of the rubidium D2 line (780 nm) are recorded and analyzed. Finally, in the third part of the experiment, which we describe in greater detail, the near-resonant magneto-optical rotation is investigated. Nonlinear light-atom interaction leads to spectacular manifestations of the resonant Faraday effect—polarization plane rotation in a magnetic field applied along the direction of light propagation radically different from the linear case. In particular, narrow (∼30 Hz) effective line widths are observed in this experiment corresponding to a rotation enhancement by some seven orders of magnitude compared to the linear Faraday rotation.
    • Fluctuation correlation spectroscopy for the advanced physics laboratory

      • Rieger, Robert; Röcker, Carlheinz; Nienhaus, G. Ulrich, Am. J. Phys. 73, 1129-1134 (2005)
      • https://doi.org/10.1119/1.2074047
      • A fluorescence correlation spectrometer is developed that is suitable for use in advanced laboratory courses. The instrument is simple to build and understand and can be constructed at a small fraction of the cost of a commercial or research-grade instrument. We demonstrate its surprisingly high performance with a simple biophysics application, the study of the binding of two complementary DNA strands. The instrument will be useful in areas of physics where precise measurements of the dynamics of fluorescent (or fluorescently labeled) molecules or nanoparticles in solution are of interest.
    • Two-photon spectroscopy of rubidium using a grating-feedback diode laser

      • Olson, Abraham J.; Carlson, Evan J.; Mayer, Shannon K., Am. J. Phys. 74, 218-223 (2006)
      • https://doi.org/10.1119/1.2173278
      • We describe an experiment for investigating the 5S1∕2→5D5∕2 two-photon transition in rubidium using a single grating-feedback diode laser operating at 778.1nm (385THz). Continuous tuning of the laser frequency over 4GHz allows for the clear resolution of the Doppler-free spectral features and allows accurate measurement of the hyperfine ground-state splitting. A direct comparison between Doppler-broadened and Doppler-free spectral features is possible because both are distinctly evident in the two-photon spectra. By independently modifying the polarization state of the two laser fields, the impact of electric dipole selection rules on the two-photon transition spectra is investigated. This experiment is a valuable addition to the advanced undergraduate laboratory because it uses much of the same equipment as the single-photon saturated absorption spectroscopy experiment performed on the 5S1∕2→5P3∕2 transition in rubidium (λ=780.24nm) and provides students with an opportunity to investigate characteristics of atomic spectra not evident in the single-photon experiment.
    • Raman scattering spectroscopy of liquid nitrogen molecules: An advanced undergraduate physics laboratory experiment

      • Sands, B. L.; Welsh, M. J.; Kin, S.; Marhatta, R.; Hinkle, J. D.; Bayram, S. B., Am. J. Phys. 75, 488-495 (2007)
      • https://doi.org/10.1119/1.2721584
      • We describe a straightforward and highly visual experiment designed to demonstrate Raman scattering spectroscopy by measuring the vibrational energy spacing of nitrogen molecules in the liquid phase. Interpretation of the spectrum teaches the principles of elastic and inelastic light scattering and the intrinsic properties of molecules. The use of a pulsed Nd:YAG laser with high peak power leads to a plethora of nonlinear optical phenomena. The presence of highly visible stimulated Raman scattering greatly enhances the normal Raman-shifted signal, allowing for a more engaging laboratory experience in comparison to traditional Raman scattering experiments.
    • Cavity ring down spectroscopy experiment for an advanced undergraduate laboratory

      • Stacewicz, T.; Wasylczyk, P.; Kowalczyk, P.; Semczuk, M., Eur. J. Phys. 28, 789 (2007)
      • https://dx.doi.org/10.1088/0143-0807/28/5/002
      • A simple experiment is described that permits advanced undergraduates to learn the principles and applications of the cavity ring down spectroscopy technique. The apparatus is used for measurements of low concentrations of NO2 produced in air by an electric discharge. We present the setup, experimental procedure, data analysis and some typical results.
    • Electromagnetically induced transparency in rubidium

      • Olson, Abraham J.; Mayer, Shannon K., Am. J. Phys. 77, 116-121 (2009)
      • https://doi.org/10.1119/1.3028309
      • We investigate ladder-type electromagnetically induced transparency (EIT) in rubidium gas. The theoretical absorption profile of a weak probe laser beam at 780.2nm (5S1∕2→5P3∕2) is modeled in the presence of a strong coupling laser beam at 776.0nm (5P3∕2→5D5∕2) and the absorption transparency window is characterized. We use two grating-feedback diode lasers and observe EIT experimentally in rubidium and compare the results to the theory. This experiment brings quantum optics into the advanced undergraduate laboratory and utilizes equipment and expertise commonly available in laboratories equipped to perform diode-laser-based absorption spectroscopy of rubidium.
    • Creating, implementing, and sustaining an advanced optical spectroscopy laboratory course

      • Blue, Jennifer; Bayram, S. Burcin; Marcum, S. Douglas, Am. J. Phys. 78, 503-509 (2010)
      • https://doi.org/10.1119/1.3327859
      • An upper-division laboratory course in atomic and molecular spectroscopy is described. Examples of outcomes that also benefit second-year physics laboratories and demonstrations in introductory courses are presented. The overarching goal that drove the development of the course was to assist students in understanding the fundamental connections between atomic and molecular spectra and the underlying structures. A selection of laboratory experiences supporting this goal, and the equipment and techniques necessary to provide them, are outlined.
    • Measuring the speed of light using beating longitudinal modes in an open-cavity HeNe laser

      • D’Orazio, Daniel J.; Pearson, Mark J.; Schultz, Justin T.; Sidor, Daniel; Best, Michael W.; Goodfellow, Kenneth M.; Scholten, Robert E.; White, James D., Am. J. Phys. 78, 524-528 (2010)
      • https://doi.org/10.1119/1.3299281
      • We describe an undergraduate laboratory that combines an accurate measurement of the speed of light, a fundamental investigation of a basic laser system, and a nontrivial use of statistical analysis. Students grapple with the existence of longitudinal modes in a laser cavity as they change the cavity length of an adjustable-cavity HeNe laser and tune the cavity to produce lasing in the TEM00 mode. For appropriate laser cavity lengths, the laser gain curve of a HeNe laser allows the simultaneous operation of multiple longitudinal modes. The difference frequency between the modes is measured using a self-heterodyne detection with a diode photodetector and a radio frequency spectrum analyzer. Asymmetric effects due to frequency pushing and frequency pulling, as well as transverse modes, are minimized by simultaneously monitoring and adjusting the mode structure as viewed with a Fabry–Pérot interferometer. The frequency spacing of longitudinal modes is proportional to the inverse of the cavity length with a proportionality constant equal to half the speed of light. By changing the length of the cavity, without changing the path length within the HeNe gas, the speed of light in air can be measured to be (2.9972±0.0002)×108 m/s, which is to high enough precision to distinguish between the speed of light in air and in vacuum.
    • Measurement of sub-natural linewidth AC Stark shifts in cold atoms: An experiment for an advanced undergraduate laboratory

      • Kleykamp, J. D.; Hachtel, A. J.; Kane, D. G.; Marshall, M. D.; Souther, N. J.; Harnish, P. K.; Bali, S., Am. J. Phys. 79, 1211-1217 (2011)
      • https://doi.org/10.1119/1.3633702
      • We measure sub-MHz AC Stark shifts, also known as light shifts, in an undergraduate laboratory setting using Raman pump-probe spectroscopy to observe sub-natural linewidth spectral features in the transmission spectrum of a weak probe beam passing through a sample of cold 85Rb atoms confined in a magneto-optical trap. To make this observation a pair of inexpensive fast photodiodes and acousto-optic modulators is needed, in addition to equipment commonly found in advanced undergraduate optics labs with laser cooling and atom trapping setups. A theoretical description of light shifts accessible to junior and senior-level physics majors is provided. (C) 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3633702]
    • Vibrational spectra of N2: An advanced undergraduate laboratory in atomic and molecular spectroscopy

      • Bayram, S. B.; Freamat, M. V., Am. J. Phys. 80, 664-669 (2012)
      • https://doi.org/10.1119/1.4722793
      • We describe an advanced undergraduate experiment to demonstrate molecular spectroscopy by measuring the vibrational energy spacing of nitrogen molecules in the gas phase. We show how the use of a simple and readily available AC discharge tube and a handheld spectrometer allows students to observe and measure the radiative collisional phenomena in the gas, and to scrutinize the resulting emission spectrum for an instructive analysis of the quantized vibrational potential of neutral as well as ionized N2.
    • Experimental determination of the Boltzmann constant: An undergraduate laboratory exercise for molecular physics or physical chemistry

      • Campbell, H. M.; Boardman, B. M.; DeVore, T. C.; Havey, D. K., Am. J. Phys. 80, 1045-1050 (2012)
      • https://doi.org/10.1119/1.4764490
      • This article describes an undergraduate laboratory exercise that uses optical spectroscopy to determine the magnitude and the uncertainty of the Boltzmann constant kb. The more accurate approach uses photoacoustic spectroscopy to measure the Doppler-broadened line profile of individual spectral lines of N2O to extract kb. Measurements and estimates of the uncertainties in the quantities needed to calculate kb from the line profiles are then used to estimate the uncertainty in kb. This experiment is unusual in that it uses advanced laser-based spectroscopy techniques to emphasize standard practices of uncertainty analysis. The core instrumentation is modular and relatively affordable; it requires a tunable single-mode laser, photoreceiver, optical cell, and vacuum pump. If this instrumentation is not available, an alternate approach can be performed which uses the intensity of each rotational transition of an infrared band to measure kb. Although there is more uncertainty using the alternate approach, low concentrations of CO2, DCl, or N2O give reasonable results for the magnitude of kb. Student assessment results indicate retention and mastery of the concept of combined measurement uncertainty.
    • Acoustic resonance spectroscopy for the advanced undergraduate laboratory

      • Franco-Villafañe, J. A.; Flores-Olmedo, E.; Báez, G.; Gandarilla-Carrillo, O.; Méndez-Sánchez, R. A., Eur. J. Phys. 33, 1761 (2012)
      • https://iopscience.iop.org/article/10.1088/0143-0807/33/6/1761/meta
      • nan
    • An undergraduate measurement of radiative broadening in atomic vapor

      • Hachtel, A. J.; Kleykamp, J. D.; Kane, D. G.; Marshall, M. D.; Worth, B. W.; Barkeloo, J. T.; Kangara, J. C. B.; Camenisch, J. C.; Gillette, M. C.; Bali, S., Am. J. Phys. 80, 740-743 (2012)
      • https://doi.org/10.1119/1.3694241
      • We show that one may quantitatively investigate radiative broadening of atomic transitions in the undergraduate laboratory using a traditional saturated absorption spectroscopy setup.
    • Measurement of the Earth’s rotational speed via Doppler shift of solar absorption lines

      • Oostra, Benjamin, Am. J. Phys. 80, 363-366 (2012)
      • https://doi.org/10.1119/1.3684841
      • This paper describes an experiment regularly presented to advanced undergraduate Physics students at the Universidad de los Andes in Bogotá, Colombia. The purpose of the experiment is to use high-resolution solar spectra to measure the horizontal speed of the laboratory caused by terrestrial rotation. Using this result, the radius of the Earth can be deduced. It is also possible to observe the Earth’s motion towards or away from the Sun, and hence compute our planet’s orbital eccentricity.
    • Collimated blue light generation in rubidium vapor

      • Kienlen, Marcus B.; Holte, Noah T.; Dassonville, Hunter A.; Dawes, Andrew M. C.; Iversen, Kurt D.; McLaughlin, Ryan M.; Mayer, Shannon K., Am. J. Phys. 81, 442-449 (2013)
      • https://doi.org/10.1119/1.4795311
      • We describe an experiment for generating and characterizing a beam of collimated blue light (CBL) in a rubidium vapor. Two low-power, grating-feedback diode lasers, operating at 780.2 nm (5S1/2→5P3/2) and 776.0 nm (5P3/2→5D5/2), respectively, provide step-wise excitation to the 5D excited state in rubidium. Under the right experimental conditions, cascade decay through the 6P excited state will yield a collimated blue (420-nm) beam of light with high temporal and spatial coherence. We investigate the production of a blue beam under a variety of experimental conditions and characterize the spatial coherence and spectral characteristics. This experiment provides advanced undergraduate students with a unique opportunity to investigate nonlinear optical phenomena in the laboratory and uses equipment that is commonly available in laboratories equipped to investigate diode-laser-based absorption spectroscopy in rubidium.
    • Inexpensive electronics and software for photon statistics and correlation spectroscopy

      • Gamari, Benjamin D.; Zhang, Dianwen; Buckman, Richard E.; Milas, Peker; Denker, John S.; Chen, Hui; Li, Hongmin; Goldner, Lori S., Am. J. Phys. 82, 712-722 (2014)
      • https://doi.org/10.1119/1.4869188
      • Single-molecule-sensitive microscopy and spectroscopy are transforming biophysics and materials science laboratories. Techniques such as fluorescence correlation spectroscopy (FCS) and single-molecule sensitive fluorescence resonance energy transfer (FRET) are now commonly available in research laboratories but are as yet infrequently available in teaching laboratories. We describe inexpensive electronics and open-source software that bridges this gap, making state-of-the-art research capabilities accessible to undergraduates interested in biophysics. We include a discussion of the intensity correlation function relevant to FCS and how it can be determined from photon arrival times. We demonstrate the system with a measurement of the hydrodynamic radius of a protein using FCS that is suitable for the undergraduate teaching laboratory. The FPGA-based electronics, which are easy to construct, are suitable for more advanced measurements as well, and several applications are described. As implemented, the system has 8 ns timing resolution, can control up to four laser sources, and can collect information from as many as four photon-counting detectors.
    • Construction of an inexpensive molecular iodine spectrometer using a self-developed Pohl wavemeter around 670 nm wavelength

      • Barthwal, Sachin; Vudayagiri, Ashok, Eur. J. Phys. 36, 55014 (2015)
      • https://dx.doi.org/10.1088/0143-0807/36/5/055014
      • We describe the construction of an inexpensive iodine spectrometer with a homemade iodine vapour cell and a self-developed wavemeter based on the Pohl interferometer, around the 670 nm wavelength. This can be easily realized in an undergraduate teaching laboratory to demonstrate the use of a diode laser interferometer using a Pohl interferometer and measurement of the wavelength using image processing techniques. A visible alternative to the infrared diode lasers, the 670 nm diode laser used here gives undergraduate students a chance to perform comprehensive though illustrative atomic physics experiments including the Zeeman effect, the Hanle effect, and the magneto-optic rotation effect with a little tweaking in the present spectrometer. The advantage of the spectrometer is its ease of construction with readily available optics, electronics, evacuation and glass-blowing facilities, and easy analysis algorithm to evaluate the wavelength. The self-developed algorithm of raster scanning and circular averaging gives the researcher insight into the basics of image processing techniques. Resolution approaching 0.5 nm can be easily achieved using such a simple setup.
    • Rotational spectra of N2+: An advanced undergraduate laboratory in atomic and molecular spectroscopy

      • Bayram, S. B.; Arndt, P. T.; Freamat, M. V., Am. J. Phys. 83, 867-872 (2015)
      • https://doi.org/10.1119/1.4926960
      • We describe an inexpensive instructional experiment that demonstrates the rotational energy levels of diatomic nitrogen, using the emission band spectrum of molecular nitrogen ionized by various processes in a commercial ac capillary discharge tube. The simple setup and analytical procedure is introduced as part of a sequence of educational experiments employed by a course of advanced atomic and molecular spectroscopy, where the study of rotational spectra is combined with the analysis of vibrational characteristics for a multifaceted picture of the quantum states of diatomic molecules.
    • Zeeman effect experiment with high-resolution spectroscopy for advanced physics laboratory

      • Taylor, Andrew S.; Hyde, Alexander R.; Batishchev, Oleg V., Am. J. Phys. 85, 565-574 (2017)
      • https://doi.org/10.1119/1.4984809
      • An experiment studying the physics underlying the Zeeman effect and the Paschen-Back effect is developed for an advanced physics laboratory. We have improved upon the standard Zeeman effect experiment by eliminating the Fabry-Perot etalon, so that virtually any emission line in the visible spectrum can be analyzed. The magnetic field is provided by neodymium magnets. Light emitted in the ∼1 T field is analyzed by a Czerny-Turner spectrograph equipped with medium-dispersion grating and small-pixel imaging CCD. A spectral resolution under 1 pm/pixel is achieved. The splitting of argon and helium lines is measured as a function of field strength. The proportionality of the splitting magnitude to the B-field strength and to λ 2 is demonstrated. The Bohr magneton is calculated and compared to the theoretical value.
    • One step beyond the electric dipole approximation: An experiment to observe the 5p → 6p forbidden transition in atomic rubidium

      • Ponciano-Ojeda, F.; Hernández-Gómez, S.; Mojica-Casique, C.; Ruiz-Martínez, E.; López-Hernández, O.; Colín-Rodríguez, R.; Ramírez-Martínez, F.; Flores-Mijangos, J.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J., Am. J. Phys. 86, 45486 (2018)
      • https://doi.org/10.1119/1.5006775
      • An advanced undergraduate experiment to study the 5 P 3 / 2 → 6 P 3 / 2 electric quadrupole transition in rubidium atoms is presented. The experiment uses two external cavity diode lasers, one operating at the D2 rubidium resonance line and the other built with commercial parts to emit at 911 nm. The lasers produce the 5 s → 5 p → 6 p excitation sequence in which the second step is the forbidden transition. Production of atoms in the 6 P 3 / 2 state is observed by detection of the 420 nm fluorescence that results from electric dipole decay into the ground state. Lines whose widths are significantly narrower than the Doppler width are used to study the hyperfine structure of the 6 P 3 / 2 state in rubidium. The spectra illustrate characteristics unique to electric dipole forbidden transitions, like the electric quadrupole selection rules; they are also used to show general aspects of two-color laser spectroscopy such as velocity selection and hyperfine pumping.
    • Little bits of diamond: Optically detected magnetic resonance of nitrogen-vacancy centers

      • Zhang, Haimei; Belvin, Carina; Li, Wanyi; Wang, Jennifer; Wainwright, Julia; Berg, Robbie; Bridger, Joshua, Am. J. Phys. 86, 225-236 (2018)
      • https://doi.org/10.1119/1.5023389
      • We give instructions for the construction and operation of a simple apparatus for performing optically detected magnetic resonance measurements on diamond samples containing high concentrations of nitrogen-vacancy (NV) centers. Each NV center has a spin degree of freedom that can be manipulated and monitored by a combination of visible and microwave radiation. We observe Zeeman shifts in the presence of small external magnetic fields and describe a simple method to optically measure magnetic field strengths with a spatial resolution of several microns. The activities described are suitable for use in an advanced undergraduate lab course, powerfully connecting core quantum concepts to cutting edge applications. An even simpler setup, appropriate for use in more introductory settings, is also presented.
    • Spectroscopy of neon for the advanced undergraduate laboratory

      • Busch, H. C.; Cooper, M. B.; Sukenik, C. I., Am. J. Phys. 87, 223-229 (2019)
      • https://doi.org/10.1119/10.0001318
      • We describe a spectroscopy experiment, suitable for upper-division laboratory courses, that investigates saturated absorption spectroscopy and polarization spectroscopy in a neon discharge. Both experiments use nearly identical components, allowing students to explore both techniques in a single apparatus. Furthermore, because the wavelength of the laser is in the visible part of the spectrum (640 nm), the experiment is well-suited for students with limited experience in optical alignment. The labs nicely complement a course in atomic or plasma physics, provide students with the opportunity to gain important technical skills in the area of optics and lasers, and can provide an introduction to radio-frequency electronics. (C) 2019 American Association of Physics Teachers.
    • Fluorescence lifetime measurements with simple correction for instrument temporal response in the advanced undergraduate laboratory

      • Gonzalez, Eduardo; Park, Seong J.; Laman, David M., Am. J. Phys. 88, 1012-1018 (2020)
      • https://doi.org/10.1119/10.0001752
      • Observation of time-dependent luminescence from excited states with a wide range of lifetimes allows students to explore the connection between selection rules and transition rates. It is fairly simple to measure microsecond and longer lifetimes with equipment common to undergraduate programs, because the instrument response time of even modest bandwidth systems is insignificant on microsecond and longer time scales. The measurement of nanosecond lifetimes, however, is more challenging, because the instrument response time is comparable to the lifetimes being measured. In this case, the instrument temporal response must be deconvolved from the observed luminescence signals in order to extract the actual excited state lifetime. We describe a method for measuring nanosecond fluorescence lifetimes in the advanced undergraduate laboratory that uses real-time analog luminescence signals instead of traditional photon counting techniques. The detection electronics of this method are fairly simple, consisting of an oscilloscope monitoring the time-dependent output of an inexpensive silicon photomultiplier. We introduce a simple and transparent method for students to characterize the instrument response and deconvolve it from the observed luminescence signals, yielding measured nanosecond fluorescence lifetimes in good agreement with the corresponding literature values obtained by time-correlated single photon counting. The limitations of silicon photomultipliers for this method of measuring nanosecond lifetimes are discussed in detail. Application of this treatment to decay processes that are not single exponential is also discussed.
    • Molecular spectroscopy as a laboratory experiment: Measurement of important parameters of sodium diatomic molecules

      • Kashem, Md Shakil Bin; Davies, Morgan; Pant, Lok; Bayram, S. Burcin, Am. J. Phys. 91, 1015-1022 (2023)
      • https://doi.org/10.1119/5.0123126
      • We present an inexpensive sodium molecular spectroscopy experiment for use in an advanced undergraduate laboratory course in physics or chemistry. The molecules were excited predominantly from the ground X 1 Σ g +( v ″ = 15) state to the B 1 Π u( v ′ = 6) state using a commercially available 532-nm broadband diode laser. The laser-induced molecular fluorescence was measured using a miniature fiber-coupled spectrometer at a resolution of 0.5 nm. The spectral peak assignments were done by comparing the observed spectrum with the calculated Franck–Condon values. Important molecular constants such as fundamental frequency, anharmonicity, bond strength, and dissociation energy of the ground electronic state were determined by using the Birge–Sponer extrapolation method. The presence of highly visible blue glowing molecules along the green laser beam creates an engaging laboratory experience. Emphasis is placed on students developing their understanding of the molecular structure, practicing molecular spectroscopic techniques, and applying knowledge of light–matter interactions to a physical system.
    • Designer spectrographs for applications in the advanced undergraduate instructional lab

      • Grove, Timothy T.; Daly, C.; Jacobs, Naomi, Am. J. Phys. 92, 221-233 (2024)
      • https://doi.org/10.1119/5.0173768
      • In an advanced undergraduate instructional laboratory, it is often necessary to analyze the spectrum of light emitted from an experimental setup. There are numerous instruments that are used to accomplish this analysis, including spectrometers and spectrographs. In this report, we present 3D-printed, low-budget spectrographs (∼ US $200), which are specifically designed for different applications. For example, one can either observe a visible spectrum over a large range of wavelengths about a desired center wavelength or achieve more precise measurements by choosing a smaller part of the visible spectrum. Our generalized design approach is well within the knowledge base of advanced undergraduate physics majors and can be applied to a wide range of applications within the visible spectrum. To demonstrate the utility of these designer spectrographs, we provide examples of recording multiple doublets in the sodium spectrum (a determination of the fine structure spin-orbit splitting of the 3p energy level) as well as measuring the wavelength differences between the hydrogen and deuterium Balmer alpha lines (a measurement of an isotope shift).
  • statistical and thermal physics

    • Boltzmann temperature: An instructional experiment for the advanced laboratory

      • Knudsen, Arthur W., Am. J. Phys. 53, 409-415 (1985)
      • https://doi.org/10.1119/1.14190
      • An experiment is described which, in a very fundamental way, introduces students at the advanced undergraduate level to the concept of temperature. The method involves analyzing the motions of electrons emitted from the hot cathode of a 6CG3 vacuum tube (the so‐called ‘‘Boltzmann method’’ of temperature determination). In addition the student finds the cathode temperature by the more conventional method of optical pyrometry. Accuracy, objectivity, and simplicity in all phases of the work have been emphasized. Agreement between the two methods of temperature determination is possible to within a small fraction of one percent. The experiment is designed for use in the advanced undergraduate laboratory.
    • Using refractive index gradients to measure diffusivity between liquids

      • Gaffney, C.; Chau, Cheuk-Kin, Am. J. Phys. 69, 821-825 (2001)
      • https://doi.org/10.1119/1.1328350
      • One most commonly thinks of refraction occurring when light strikes at an angle to an interface separating two regions with different refractive indices. However, a light ray traveling normal to such an interface will also be refracted, if the second region has a refractive index gradient parallel to the interface plane. If liquid–liquid interdiffusion produces such a gradient in the second region, then one can infer the diffusivity of solute particles by measuring the time-dependent refraction. We have performed such diffusion experiments with three different aqueous solutions and found reasonably good agreement with diffusivity values given in the literature. The experimental setup and data analysis are simple enough for an undergraduate student to complete in a few weeks, making this investigation ideal for inclusion in an advanced laboratory course.
    • Finding viscosity of liquids from Brownian motion at students' laboratory

      • Greczyło, Tomasz; Dębowska, Ewa, Eur. J. Phys. 26, 827 (2005)
      • https://dx.doi.org/10.1088/0143-0807/26/5/015
      • Brownian motion appears to be a good subject for investigation at advanced students' laboratory [1]. The paper presents such an investigation carried out in Physics Laboratory II at the Institute of Experimental Physics of Wroclaw University. The experiment has been designed to find viscosity of liquids from Brownian motion phenomenon. Authors use modern technology that helps to proceed with measurements and makes the procedure less time and effort consuming. Discussion of the process of setting up the experiment and the results obtained for three different solutions of glycerin in water are presented. Advantages and disadvantages of the apparatus are pointed out along with descriptions of possible future uses.
    • The time, size, viscosity, and temperature dependence of the Brownian motion of polystyrene microspheres

      • Jia, Dongdong; Hamilton, Jonathan; Zaman, Lenu M.; Goonewardene, Anura, Am. J. Phys. 75, 111-115 (2007)
      • https://doi.org/10.1119/1.2386163
      • An upper division undergraduate laboratory module to study Brownian motion was developed using polystyrene microspheres suspended in a sample liquid cell that was isolated from its surroundings. The dependence of the Brownian motion of the microspheres on their radius, the time, the viscosity of the suspension liquid, and the temperature were measured using a CCD camera interfaced with a frame grabber and a computer. The motion of each particle was monitored for 5minutes and was found to be consistent with the Langevin formula for Brownian motion.
    • Determination of the diffusion coefficient between corn syrup and distilled water using a digital camera

      • Ray, E.; Bunton, P.; Pojman, J. A., Am. J. Phys. 75, 903-906 (2007)
      • https://doi.org/10.1119/1.2752819
      • A simple technique for determining the diffusion coefficient between two miscible liquids is presented based on observing concentration-dependent ultraviolet-excited fluorescence using a digital camera. The ultraviolet-excited visible fluorescence of corn syrup is proportional to the concentration of the syrup. The variation of fluorescence with distance from the transition zone between the fluids is fit by the Fick’s law solution to the diffusion equation. By monitoring the concentration at successive times, the diffusion coefficient can be determined in otherwise transparent materials. The technique is quantitative and makes measurement of diffusion accessible in the advanced undergraduate physics laboratory.
    • A simple optical probe of transient heat conduction

      • Brody, Jed; Andreae, Phillip; Robinson, C. Andrew, Am. J. Phys. 78, 529-531 (2010)
      • https://doi.org/10.1119/1.3299282
      • We use a laser beam and a stopwatch to investigate transient heat conduction in Plexiglas and glycerol samples chilled by ice water. The deflection of the laser beam is proportional to the thermal gradient in the sample. Measurements of the beam deflection allow us to calculate the thermal gradient as a function of time. Our empirical results fit the theoretical predictions very well and show an initial increase in the thermal gradient followed by a gradual decrease as the entire sample approaches the temperature of ice water. The procedure is simple and can be used as a lecture demonstration, an afternoon's experiment, or an extended investigation in an advanced laboratory course.
    • Simple, simpler, simplest: Spontaneous pattern formation in a commonplace system

      • Strombom, Evelyn H.; Caicedo-Carvajal, Carlos E.; Thyagu, N. Nirmal; Palumbo, Daniel; Shinbrot, Troy, Am. J. Phys. 80, 578-586 (2012)
      • https://doi.org/10.1119/1.4709384
      • In 1855, Lord Kelvin's brother, James Thomson, wrote a paper describing "certain curious motions" on liquid surfaces. In the present paper, we describe several curious motions produced in the simplest possible manner: by introducing a droplet of food coloring into a shallow dish of water. These motions include the spontaneous formation of labyrinthine stripes, the periodic pulsation leading to chaotic stretching and folding, and the formation of migrating slugs of coloring. We use this simple experiment to demonstrate that the formation of ordered macroscopic patterns is consistent with the requirement of the second law of Thermodynamics that microscopic disorder must increase. This system is suitable for undergraduate experimentation and can be modeled by advanced students in a straightforward finite difference simulation that reproduces the labyrinths and other patterns. (C) 2012 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4709384]
    • Improving the quantification of Brownian motion

      • Catipovic, Marco A.; Tyler, Paul M.; Trapani, Josef G.; Carter, Ashley R., Am. J. Phys. 81, 485-491 (2013)
      • https://doi.org/10.1119/1.4803529
      • Brownian motion experiments have become a staple of the undergraduate advanced laboratory, yet quantification of these experiments is difficult, typically producing errors of 10%–15% or more. Here, we discuss the individual sources of error in the experiment: sampling error, uncertainty in the diffusion coefficient, tracking error, vibration, and microscope drift. We model each source of error using theoretical and computational methods and compare the model to our experimental data. Finally, we describe various ways to reduce each source of error to less than 1%, improving the quantification of Brownian motion.
    • Exploring the thermodynamics of a rubber band

      • Roundy, David; Rogers, Michael, Am. J. Phys. 81, 20-23 (2013)
      • https://doi.org/10.1119/1.4757908
      • We describe an upper-division experiment in thermal physics where students measure the tension of a rubber band as a function of temperature and length and use a Maxwell relation to find the change in internal energy and entropy for an isothermal stretch. This allows students to experimentally check the predictions of the entropic spring model for elastomers and observe that the entropy does indeed decrease as a rubber band is stretched.
    • Two-dimensional heat flow apparatus

      • McDougall, Patrick; Ayars, Eric, Am. J. Phys. 82, 620-623 (2014)
      • https://doi.org/10.1119/1.4867053
      • We have created an apparatus to quantitatively measure two-dimensional heat flow in a metal plate using a grid of temperature sensors read by a microcontroller. Real-time temperature data are collected from the microcontroller by a computer for comparison with a computational model of the heat equation. The microcontroller-based sensor array allows previously unavailable levels of precision at very low cost, and the combination of measurement and modeling makes for an excellent apparatus for the advanced undergraduate laboratory course. (C) 2014 American Association of Physics Teachers.
    • Thermal diffusivity imaging

      • Gfroerer, Tim; Phillips, Ryan; Rossi, Peter, Am. J. Phys. 83, 923-927 (2015)
      • https://doi.org/10.1119/1.4928277
      • The tip of a rod is heated with a torch and brought into contact with the center of a metal sheet. A thermal camera is then used to image the temperature profile of the surface as a function of time. The infrared camera is capable of recording radiometric data with 1 mK resolution in nearly 105 pixels, so thermal diffusion can be monitored with unprecedented precision. With a frame rate of approximately 10 Hz, the pace of the data acquisition minimizes the loss of accuracy due to inevitable cooling mechanisms. We report diffusivity constants equal to 1.23 ± 0.06 cm2/s in copper and 0.70 ± 0.05 cm2/s in aluminum. The behavior is modeled with a straightforward but oddly under-utilized one-dimensional finite difference method.
    • Undergraduate experiments on statistical optics

      • Scholz, Ruediger; Friege, Gunnar; Weber, Kim-Alessandro, Eur. J. Phys. 37, 55302 (2016)
      • https://dx.doi.org/10.1088/0143-0807/37/5/055302
      • Since the pioneering experiments of Forrester et al (1955 Phys. Rev. 99 1691) and Hanbury Brown and Twiss (1956 Nature 177 27; Nature 178 1046), along with the introduction of the laser in the 1960s, the systematic analysis of random fluctuations of optical fields has developed to become an indispensible part of physical optics for gaining insight into features of the fields. In 1985 Joseph W Goodman prefaced his textbook on statistical optics with a strong commitment to the ‘tools of probability and statistics’ (Goodman 2000 Statistical Optics (New York: John Wiley & Sons Inc.)) in the education of advanced optics. Since then a wide range of novel undergraduate optical counting experiments and corresponding pedagogical approaches have been introduced to underpin the rapid growth of the interest in coherence and photon statistics. We propose low cost experimental steps that are a fair way off ‘real’ quantum optics, but that give deep insight into random optical fluctuation phenomena: (1) the introduction of statistical methods into undergraduate university optical lab work, and (2) the connection between the photoelectrical signal and the characteristics of the light source. We describe three experiments and theoretical approaches which may be used to pave the way for a well balanced growth of knowledge, providing students with an opportunity to enhance their abilities to adapt the ‘tools of probability and statistics’.
    • Thermoelectric effects and applications: an advanced physics laboratory experiment

      • Aqra, R.; AbualRob, K.; Jaeger, H.; Eid, K. F., Eur. J. Phys. 43, 55101 (2022)
      • https://dx.doi.org/10.1088/1361-6404/ac72d3
      • We developed a simple, inexpensive undergraduate laboratory experiment covering concepts and applications related to thermoelectric effects. Students use commercially available thermoelectric plates for producing electric current or for cooling and heating, then utilize them to perform experimental investigations that involve cooling. These investigations include studying supercooling and flash-freezing of water, as well as the temperature dependence of the resistivity of metals and semiconductors. The experiment allows students to easily add more components to investigate additional phenomena, thus lending itself as a potential open-ended ‘final project’ in the lab. The activities emphasize experiment design and scientific investigation. They also develop some of the main goals of advanced physics laboratories, such as the exposure to new technologies and experimental skills, data collection and automation/control, as well as data analysis and the clear communication of the results. This experiment can be integrated into the physics curriculum of electronics or advanced laboratory courses at the sophomore or higher levels.
  • vacuum techniques

    • An advanced laboratory in nuclear-isotope mass spectroscopy

      • Shaheen, S. A.; Shapiro, M.; Becchetti, F. D., Am. J. Phys. 66, 1048-1055 (1998)
      • https://doi.org/10.1119/1.19044
      • We describe an experiment in nuclear-isotope mass spectroscopy, suitable for an advanced physics laboratory, which utilizes a relatively inexpensive commercial 60°-dipole residual gas analyzer. Students measure the terrestrial abundance of the isotope Ne22 relative to Ne20 and compare this with recent measurements of this ratio in meteorites. These ratios provide clues to the astrophysical sites, astrophysical processes, and nuclear reactions which formed these isotopes. The mass spectrometer is also used as a residual gas analyzer to examine the gas composition (O2, N2, H2O,…) at various pressures in a typical vacuum system. This gives students insight into the design of vacuum apparatus including the optimal selection of components such as vacuum pumps for particular applications.
  • False

    • A simple electronic circuit demonstrating Hopf bifurcation for an advanced undergraduate laboratory

      • Deo, Ishan; Khare, Krishnacharya, Am. J. Phys. 90, 908-913 (2022)
      • https://doi.org/10.1119/5.0062969
      • A nonlinear electronic circuit comprising of three nodes with a feedback loop is analyzed. The system has two stable states, a uniform state and a sinusoidal oscillating state, and it transitions from one to another by means of a Hopf bifurcation. The stability of this system is analyzed with nonlinear equations derived from a repressilator-like transistor circuit. The apparatus is simple and inexpensive, and the experiment demonstrates aspects of nonlinear dynamical systems in an advanced undergraduate laboratory setting.